Update README

Release 1.0.0

.github/dependabot.yml

@@ -0,0 +1,15 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "gomod"
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "quarterly"
+  - package-ecosystem: "github-actions"
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "quarterly"

.github/workflows/build-release.yml

@@ -0,0 +1,35 @@
+name: Release Go Binaries
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  releases-matrix:
+    name: Release Go Binary
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        goos: [linux, darwin]
+        goarch: ["386", amd64, arm, arm64]
+        exclude:
+          - goarch: "386"
+            goos: darwin
+          - goarch: arm
+            goos: darwin
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: wangyoucao577/go-release-action@v1
+        with:
+          binary_name: "goptimize"
+          asset_name: "goptimize-${{ matrix.goos }}-${{ matrix.goarch }}"
+          extra_files: LICENSE README.md
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          md5sum: false
+          overwrite: true
+          goos: ${{ matrix.goos }}
+          goarch: ${{ matrix.goarch }}
+          pre_command: export GO386=softfloat CGO_ENABLED=0
+          ldflags: -s -w -X "main.version=${{ github.ref_name }}"

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,72 @@
+# For most projects, this workflow file will not need changing; you simply need
+# to commit it to your repository.
+#
+# You may wish to alter this file to override the set of languages analyzed,
+# or to provide custom queries or build logic.
+#
+# ******** NOTE ********
+# We have attempted to detect the languages in your repository. Please check
+# the `language` matrix defined below to confirm you have the correct set of
+# supported CodeQL languages.
+#
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ "develop" ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ "develop" ]
+  schedule:
+    - cron: '34 23 * * 4'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'go' ]
+        # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python', 'ruby' ]
+        # Learn more about CodeQL language support at https://aka.ms/codeql-docs/language-support
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    # Initializes the CodeQL tools for scanning.
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v3
+      with:
+        languages: ${{ matrix.language }}
+        # If you wish to specify custom queries, you can do so here or in a config file.
+        # By default, queries listed here will override any specified in a config file.
+        # Prefix the list here with "+" to use these queries and those in the config file.
+        
+        # Details on CodeQL's query packs refer to : https://docs.github.com/en/code-security/code-scanning/automatically-scanning-your-code-for-vulnerabilities-and-errors/configuring-code-scanning#using-queries-in-ql-packs
+        # queries: security-extended,security-and-quality
+
+        
+    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+    # If this step fails, then you should remove it and run the build manually (see below)
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@v3
+
+    # ℹ️ Command-line programs to run using the OS shell.
+    # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
+
+    #   If the Autobuild fails above, remove it and uncomment the following three lines. 
+    #   modify them (or add more) to build your code if your project, please refer to the EXAMPLE below for guidance.
+
+    # - run: |
+    #   echo "Run, Build Application using script"
+    #   ./location_of_script_within_repo/buildscript.sh
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v3

.github/workflows/tests.yml

@@ -0,0 +1,20 @@
+name: Tests
+on:
+  pull_request:
+    branches: [develop, "feature/**"]
+  push:
+    branches: [develop, "feature/**"]
+
+jobs:
+  golangci:
+    name: golangci-lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: stable
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v8
+        with:
+          version: v2.1

CHANGELOG.md

@@ -1,21 +1,44 @@
 # Changelog
 
-## [dev]
+## [1.0.0]
+
+- Use ghru/v2 for latest version checks and self-update functionality
+- Refactor code for consistency and error handling improvements
+- Update Go dependencies
+- Use GitHub Actions to build release binaries
+- Add quarterly dependabot module update
+- Add code quality checks & linting (golangci-lint)
+
+## [0.2.3]
+
+- Switch to kovidgoyal/imaging to address CVE-2023-36308
+
+## [0.2.2]
+
+- Optionally preserve exif data for supported formats
+- Update Go modules
+
+## [0.2.1]
+
+- Update core modules
+
+## [0.2.0]
+
+- Add threaded option (`-t`) to use all CPU cores
+
+## [0.1.0]
 
 - Switch to go mods - go (>= 1.11 required)
 - Switch to axllent/semver for app updating
 
-
 ## [0.0.3]
 
 - Detect & skip animated GIFs
 
-
 ## [0.0.2]
 
 - Switch to [pflag](https://github.com/spf13/pflag) for better flag management
 
-
 ## [0.0.1]
 
 - Initial release

LICENSE

@@ -1,16 +1,21 @@
-Copyright 2019 Ralph Slooten
+The MIT License (MIT)
+Copyright (c) 2019-Now() Ralph Slooten
 
-Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+Permission is hereby granted, free of charge, to any person obtaining
-and associated documentation files (the "Software"), to deal in the Software without restriction,
+a copy of this software and associated documentation files (the
-including without limitation the rights to use, copy, modify, merge, publish, distribute,
+"Software"), to deal in the Software without restriction, including
-sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
+without limitation the rights to use, copy, modify, merge, publish,
-furnished to do so, subject to the following conditions:
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
 
-The above copyright notice and this permission notice shall be included in all copies or
+The above copyright notice and this permission notice shall be
-substantial portions of the Software.
+included in all copies or substantial portions of the Software.
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Makefile

@@ -1,23 +0,0 @@
-TAG=`git describe --tags`
-VERSION ?= `git describe --tags`
-LDFLAGS=-ldflags "-s -w -X main.version=${VERSION}"
-
-build = echo "\n\nBuilding $(1)-$(2)" && GOOS=$(1) GOARCH=$(2) go build ${LDFLAGS} -o dist/goptimize_${VERSION}_$(1)_$(2) \
-	&& bzip2 dist/goptimize_${VERSION}_$(1)_$(2)
-
-goptimize: *.go go.*
-	go build ${LDFLAGS} -o goptimize
-	rm -rf /tmp/go-*
-
-clean:
-	rm -f goptimize
-
-release:
-	mkdir -p dist
-	rm -f dist/goptimize_${VERSION}_*
-	$(call build,linux,amd64)
-	$(call build,linux,386)
-	$(call build,linux,arm)
-	$(call build,linux,arm64)
-	$(call build,darwin,amd64)
-	$(call build,darwin,386)

README.md

@@ -1,8 +1,8 @@
-# Goptimizer - downscales and optimizes images
+# Goptimize - downscales and optimizes images
 
 [![Go Report Card](https://goreportcard.com/badge/github.com/axllent/goptimize)](https://goreportcard.com/report/github.com/axllent/goptimize)
 
-Goptimizer is a commandline utility written in Golang. It downscales and optimizes JPEG, PNG, GIF, TIFF and BMP files.
+Goptimize is a command-line utility written in Go. It downscales and optimizes JPEG, PNG, GIF, TIFF and BMP files.
 
 Image downscaling/rotation is done within goptimize (`-m <width>x<height>`, see [Usage](#usage-options)), however optimization is done using the following additional tools (if they are installed):
 
@@ -11,19 +11,17 @@ Image downscaling/rotation is done within goptimize (`-m <width>x<height>`, see
 - pngquant
 - gifsicle
 
-
 ## Notes
 
 Both `jpegoptim` & `jpegtran` have almost identical optimization, so if both are installed then just `jpegtran` is used for JPG optimization. PNG optimization however will run through both `optipng` & `pngquant` (if installed) as this can result in better optimization.
 
 It is highly recommended to install the necessary optimization tools, however they are not required to run goptimize.
 
-Goptimize will remove all exif data from JPEG files, auto-rotating those that depend on it for orientation.
+GGoptimize will by default remove all EXIF data from JPEG files and automatically rotate those that rely on it for orientation. This can be disabled by adding the `-e` flag.
 
 It will also preserve (by default) the file's original modification times (`-p=false` to disable).
 
-Animated GIF files are not supported and automatically get skipped.
+Animated GIF files are not supported and are ignored.
-
 
 ## Usage options
 
@@ -35,6 +33,7 @@ Options:
   -m, --max string         downscale to a maximum width & height in pixels (<width>x<height>)
   -o, --out string         output directory (default overwrites original)
   -p, --preserve           preserve file modification times (default true)
+  -t, --threaded           run multi-threaded (use all CPU cores)
   -u, --update             update to latest release
   -v, --version            show version number
   -h, --help               show help
@@ -45,7 +44,6 @@ Options:
       --optipng string     optipng binary (default "optipng")
 ```
 
-
 ## Examples
 
 - `./goptimize image.png` - optimize a PNG file
@@ -53,23 +51,10 @@ Options:
 - `./goptimize -m 1200x0 image.jpg` - optimize and downscale a JPG file to a maximum size of width of 1200px
 - `./goptimize -o out/ image.jpg` - optimize a JPG file and save it to `out/`
 
-
 ## Install
 
-Download the appropriate binary from the [releases](https://github.com/axllent/goptimize/releases/latest), or if you have golang installed 
+Download the appropriate binary from the [releases](https://github.com/axllent/goptimize/releases/latest), or if you have golang installed you can install from source:
-
-
-### Build requirements
-
-Go >= 1.11 required.
 
 ```
-go get github.com/axllent/goptimize
+go install github.com/axllent/goptimize@latest
 ```
-
-## TODO
-
-Some ideas for the future:
-
-- Dry run
-- Option to copy exif data (how?)

exifcopy.go

@@ -0,0 +1,171 @@
+// https://stackoverflow.com/a/76779756
+package main
+
+import (
+	"bufio"
+	"errors"
+	"io"
+	"os"
+)
+
+const (
+	soi       = 0xD8
+	eoi       = 0xD9
+	sos       = 0xDA
+	exif      = 0xE1
+	copyright = 0xEE
+	comment   = 0xFE
+)
+
+func isMetaTagType(tagType byte) bool {
+	// Adapt as needed
+	return tagType == exif || tagType == copyright || tagType == comment
+}
+
+func copySegments(dst *bufio.Writer, src *bufio.Reader, filterSegment func(tagType byte) bool) error {
+	var buf [2]byte
+	_, err := io.ReadFull(src, buf[:])
+	if err != nil {
+		return err
+	}
+	if buf != [2]byte{0xFF, soi} {
+		return errors.New("expected SOI")
+	}
+	for {
+		_, err := io.ReadFull(src, buf[:])
+		if err != nil {
+			return err
+		}
+		if buf[0] != 0xFF {
+			return errors.New("invalid tag type")
+		}
+		if buf[1] == eoi {
+			// Hacky way to check for EOF
+			_, err := src.Read(buf[:1])
+			if err != nil && err != io.EOF {
+				return err
+			}
+			// don't return an error as some cameras add the exif data at the end.
+			// if n > 0 {
+			// 	return errors.New("EOF expected after EOI")
+			// }
+			return nil
+		}
+		sos := buf[1] == 0xDA
+		filter := filterSegment(buf[1])
+		if filter {
+			_, err = dst.Write(buf[:])
+			if err != nil {
+				return err
+			}
+		}
+
+		_, err = io.ReadFull(src, buf[:])
+		if err != nil {
+			return err
+		}
+		if filter {
+			_, err = dst.Write(buf[:])
+			if err != nil {
+				return err
+			}
+		}
+
+		// Note: Includes the length, but not the tag, so subtract 2
+		tagLength := ((uint16(buf[0]) << 8) | uint16(buf[1])) - 2
+		if filter {
+			_, err = io.CopyN(dst, src, int64(tagLength))
+		} else {
+			_, err = src.Discard(int(tagLength))
+		}
+		if err != nil {
+			return err
+		}
+		if sos {
+			// Find next tag `FF xx` in the stream where `xx != 0` to skip ECS
+			// See https://stackoverflow.com/questions/2467137/parsing-jpeg-file-format-format-of-entropy-coded-segments-ecs
+			for {
+				bytes, err := src.Peek(2)
+				if err != nil {
+					return err
+				}
+				if bytes[0] == 0xFF {
+					data, rstMrk := bytes[1] == 0, bytes[1] >= 0xD0 && bytes[1] <= 0xD7
+					if !data && !rstMrk {
+						break
+					}
+				}
+				if filter {
+					err = dst.WriteByte(bytes[0])
+					if err != nil {
+						return err
+					}
+				}
+				_, err = src.Discard(1)
+				if err != nil {
+					return err
+				}
+			}
+		}
+	}
+}
+
+func copyMetadata(outImagePath, imagePath, metadataImagePath string) error {
+	outFile, err := os.Create(outImagePath)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = outFile.Close() }()
+	writer := bufio.NewWriter(outFile)
+
+	imageFile, err := os.Open(imagePath)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = imageFile.Close() }()
+	imageReader := bufio.NewReader(imageFile)
+
+	metaFile, err := os.Open(metadataImagePath)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = metaFile.Close() }()
+	metaReader := bufio.NewReader(metaFile)
+
+	_, err = writer.Write([]byte{0xFF, soi})
+	if err != nil {
+		return err
+	}
+
+	// Copy metadata segments
+	// It seems that they need to come first!
+	err = copySegments(writer, metaReader, isMetaTagType)
+	if err != nil {
+		return err
+	}
+	// Copy all non-metadata segments
+	err = copySegments(writer, imageReader, func(tagType byte) bool {
+		return !isMetaTagType(tagType)
+	})
+	if err != nil {
+		return err
+	}
+
+	_, err = writer.Write([]byte{0xFF, eoi})
+	if err != nil {
+		return err
+	}
+
+	// Flush the writer, otherwise the last couple buffered writes (including the EOI) won't get written!
+	return writer.Flush()
+}
+
+func exifCopy(fromPath, toPath string) error {
+	copyPath := toPath + "~"
+	err := os.Rename(toPath, copyPath)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = os.Remove(copyPath) }()
+	return copyMetadata(toPath, copyPath, fromPath)
+}

go.mod

@@ -1,10 +1,14 @@
 module github.com/axllent/goptimize
 
-go 1.13
+go 1.23.0
+
+toolchain go1.23.1
 
 require (
-	github.com/axllent/ghru v1.1.3
+	github.com/axllent/ghru/v2 v2.0.1
-	github.com/disintegration/imaging v1.6.1
+	github.com/kovidgoyal/imaging v1.6.4
-	github.com/spf13/pflag v1.0.5
+	github.com/spf13/pflag v1.0.6
-	golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8
+	golang.org/x/image v0.28.0
 )
+
+require golang.org/x/mod v0.25.0 // indirect

go.sum

@@ -1,12 +1,10 @@
-github.com/axllent/ghru v1.1.3 h1:n0jYsuqCYaHHAR6DraXZl8hpBY4j0XV47y5Lyym/jGo=
+github.com/axllent/ghru/v2 v2.0.1 h1:/9XHbMqJRGRxlyNMq2XiHQpBLz7hlq8xCdgJ4ZhjCoM=
-github.com/axllent/ghru v1.1.3/go.mod h1:rFvMhcO1UAv2Cv6bXscS8EOc7qqNpfe8ZLp23utzs88=
+github.com/axllent/ghru/v2 v2.0.1/go.mod h1:seMMjx8/0r5ZAL7c0vwTPIRoyN0AoTUqAylZEWZWGK4=
-github.com/axllent/semver v0.0.0-20191103011746-394cefa91ee9 h1:LHNcCfePzgC/agAJs5a/5K3hFo8uW04bEdDKDkoX4do=
+github.com/kovidgoyal/imaging v1.6.4 h1:K0idhRPXnRrJBKnBYcTfI1HTWSNDeAn7hYDvf9I0dCk=
-github.com/axllent/semver v0.0.0-20191103011746-394cefa91ee9/go.mod h1:2xSPzvG8n9mRfdtxSvWvfTfQGWfHsMsHO1iZnKATMSc=
+github.com/kovidgoyal/imaging v1.6.4/go.mod h1:bEIgsaZmXlvFfkv/CUxr9rJook6AQkJnpB5EPosRfRY=
-github.com/disintegration/imaging v1.6.1 h1:JnBbK6ECIZb1NsWIikP9pd8gIlTIRx7fuDNpU9fsxOE=
+github.com/spf13/pflag v1.0.6 h1:jFzHGLGAlb3ruxLB8MhbI6A8+AQX/2eW4qeyNZXNp2o=
-github.com/disintegration/imaging v1.6.1/go.mod h1:xuIt+sRxDFrHS0drzXUlCJthkJ8k7lkkUojDSR247MQ=
+github.com/spf13/pflag v1.0.6/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
-github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
+golang.org/x/image v0.28.0 h1:gdem5JW1OLS4FbkWgLO+7ZeFzYtL3xClb97GaUzYMFE=
-github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+golang.org/x/image v0.28.0/go.mod h1:GUJYXtnGKEUgggyzh+Vxt+AviiCcyiwpsl8iQ8MvwGY=
-golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=
+golang.org/x/mod v0.25.0 h1:n7a+ZbQKQA/Ysbyb0/6IbB1H/X41mKgbhfv7AfG/44w=
-golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8 h1:hVwzHzIUGRjiF7EcUjqNxk3NCfkPxbDKRdnNE1Rpg0U=
+golang.org/x/mod v0.25.0/go.mod h1:IXM97Txy2VM4PJ3gI61r1YEk/gAj6zAHN3AdZt6S9Ww=
-golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

goptimize.go

@@ -2,23 +2,23 @@ package main
 
 import (
 	"fmt"
+	"image"
 	"image/gif"
 	"image/jpeg"
 	"image/png"
 	"io"
-	"io/ioutil"
 	"math"
 	"os"
 	"os/exec"
 	"path/filepath"
 
-	"github.com/disintegration/imaging"
+	"github.com/kovidgoyal/imaging"
 	"golang.org/x/image/bmp"
 	"golang.org/x/image/tiff"
 )
 
 // Goptimize downscales and optimizes an existing image
-func Goptimize(file string) {
+func goptimize(file string) {
 	info, err := os.Stat(file)
 
 	if err != nil {
@@ -31,12 +31,21 @@ func Goptimize(file string) {
 		return
 	}
 
-	// open original, rotate if necessary
+	var src image.Image
-	src, err := imaging.Open(file, imaging.AutoOrientation(true))
 
-	if err != nil {
+	if !copyExif {
-		fmt.Printf("Error: %v (%s)\n", err, file)
+		// rotate if necessary
-		return
+		src, err = imaging.Open(file, imaging.AutoOrientation(true))
+		if err != nil {
+			fmt.Printf("Error: %v (%s)\n", err, file)
+			return
+		}
+	} else {
+		src, err = imaging.Open(file)
+		if err != nil {
+			fmt.Printf("Error: %v (%s)\n", err, file)
+			return
+		}
 	}
 
 	format, err := imaging.FormatFromFilename(file)
@@ -48,7 +57,7 @@ func Goptimize(file string) {
 
 	if format.String() == "GIF" {
 		// return if GIF is animated - unsupported
-		if err := IsGIFAnimated(file); err != nil {
+		if err := isGIFAnimated(file); err != nil {
 			fmt.Printf("Error: animated GIF not supported (%v)\n", file)
 			return
 		}
@@ -83,14 +92,14 @@ func Goptimize(file string) {
 	resultW := dstBounds.Dx()
 	resultH := dstBounds.Dy()
 
-	tmpFile, err := ioutil.TempFile(os.TempDir(), "Goptimized-")
+	tmpFile, err := os.CreateTemp(os.TempDir(), "Goptimized-")
 
 	if err != nil {
 		fmt.Printf("Error: cannot create temporary file: %v\n", err)
 		return
 	}
 
-	defer os.Remove(tmpFile.Name())
+	defer func() { _ = os.Remove(tmpFile.Name()) }()
 
 	switch imgType := format.String(); imgType {
 	case "JPEG":
@@ -118,25 +127,35 @@ func Goptimize(file string) {
 
 	// immediately close the temp file to release pointers
 	// so we can modify it with system processes
-	tmpFile.Close()
+	if err := tmpFile.Close(); err != nil {
+		fmt.Printf("Error closing temporary file: %v\n", err)
+		return
+	}
 
 	// run through optimizers
 	if format.String() == "JPEG" {
 		// run one or the other, running both has no advantage
 		if jpegtran != "" {
-			RunOptimizer(tmpFilename, true, jpegtran, "-optimize", "-outfile")
+			runOptimizer(tmpFilename, true, jpegtran, "-optimize", "-outfile")
 		} else if jpegoptim != "" {
-			RunOptimizer(tmpFilename, false, jpegoptim, "-f", "-s", "-o")
+			runOptimizer(tmpFilename, false, jpegoptim, "-f", "-s", "-o")
+		}
+
+		if copyExif {
+			if err := exifCopy(file, tmpFilename); err != nil {
+				fmt.Printf("Error copying exif data: %v (%s)\n", err, file)
+				return
+			}
 		}
 	} else if format.String() == "PNG" {
 		if pngquant != "" {
-			RunOptimizer(tmpFilename, true, pngquant, "-f", "--output")
+			runOptimizer(tmpFilename, true, pngquant, "-f", "--output")
 		}
 		if optipng != "" {
-			RunOptimizer(tmpFilename, true, optipng, "-out")
+			runOptimizer(tmpFilename, true, optipng, "-out")
 		}
 	} else if format.String() == "GIF" && gifsicle != "" {
-		RunOptimizer(tmpFilename, true, gifsicle, "-o")
+		runOptimizer(tmpFilename, true, gifsicle, "-o")
 	}
 
 	// re-open modified temporary file
@@ -146,7 +165,7 @@ func Goptimize(file string) {
 		return
 	}
 
-	defer tmpFile.Close()
+	defer func() { _ = tmpFile.Close() }()
 
 	// get th eoriginal file stats
 	srcStat, _ := os.Stat(file)
@@ -171,7 +190,7 @@ func Goptimize(file string) {
 			return
 		}
 
-		defer out.Close()
+		defer func() { _ = out.Close() }()
 
 		if _, err := io.Copy(out, tmpFile); err != nil {
 			fmt.Printf("Error overwriting original file: %v\n", err)
@@ -185,22 +204,26 @@ func Goptimize(file string) {
 			}
 		}
 
-		fmt.Printf("Goptimized %s (%dx%d %s > %s %v%%)\n", dstFile, resultW, resultH, ByteCountSI(srcSize), ByteCountSI(dstSize), savedPercent)
+		fmt.Printf("Optimized %s (%dx%d %s > %s %v%%)\n", dstFile, resultW, resultH, byteCountSI(srcSize), byteCountSI(dstSize), savedPercent)
 	} else {
 		// if the output directory is not the same,
 		// then write a copy of the original file
 		if outputDir != "" {
 			out, err := os.Create(dstFile)
+			if err != nil {
+				fmt.Printf("Error creating new file: %v\n", err)
+				return
+			}
+
+			defer func() { _ = out.Close() }()
+
+			orig, err := os.Open(file)
 			if err != nil {
 				fmt.Printf("Error opening original file: %v\n", err)
 				return
 			}
 
-			defer out.Close()
+			defer func() { _ = orig.Close() }()
-
-			orig, _ := os.Open(file)
-
-			defer orig.Close()
 
 			if _, err := io.Copy(out, orig); err != nil {
 				fmt.Printf("Error ovewriting original file: %v\n", err)
@@ -214,36 +237,35 @@ func Goptimize(file string) {
 				}
 			}
 
-			fmt.Printf("Copied %s (%dx%d %s %v%%)\n", dstFile, srcW, srcH, ByteCountSI(srcSize), 0)
+			fmt.Printf("Copied %s (%dx%d %s %v%%)\n", dstFile, srcW, srcH, byteCountSI(srcSize), 0)
 		} else {
 			// we didn't actually change anything
-			fmt.Printf("Skipped %s (%dx%d %s %v%%)\n", dstFile, srcW, srcH, ByteCountSI(srcSize), 0)
+			fmt.Printf("Skipped %s (%dx%d %s %v%%)\n", dstFile, srcW, srcH, byteCountSI(srcSize), 0)
 		}
 	}
 
 }
 
-// RunOptimizer will run the specified command on a copy of the temporary file,
+// runOptimizer will run the specified command on a copy of the temporary file,
 // and overwrite it if the output is smaller than the original
-func RunOptimizer(src string, outFileArg bool, args ...string) {
+func runOptimizer(src string, outFileArg bool, args ...string) {
 	// create a new temp file
-	tmpFile, err := ioutil.TempFile(os.TempDir(), "Goptimized-")
+	tmpFile, err := os.CreateTemp(os.TempDir(), "goptimize-")
 
 	if err != nil {
 		fmt.Printf("Cannot create temporary file: %v\n", err)
 		return
 	}
 
-	defer os.Remove(tmpFile.Name())
+	defer func() { _ = os.Remove(tmpFile.Name()) }()
 
 	source, err := os.Open(src)
-
 	if err != nil {
 		fmt.Printf("Cannot open temporary file: %v\n", err)
 		return
 	}
 
-	defer source.Close()
+	defer func() { _ = source.Close() }()
 
 	if _, err := io.Copy(tmpFile, source); err != nil {
 		fmt.Printf("Cannot copy source file: %v\n", err)
@@ -273,8 +295,8 @@ func RunOptimizer(src string, outFileArg bool, args ...string) {
 	dstSize := dstStat.Size()
 
 	// ensure file pointers are closed before renaming
-	tmpFile.Close()
+	func() { _ = tmpFile.Close() }()
-	source.Close()
+	func() { _ = source.Close() }()
 
 	if dstSize < srcSize {
 		if err := os.Rename(tmpFilename, src); err != nil {
@@ -285,7 +307,7 @@ func RunOptimizer(src string, outFileArg bool, args ...string) {
 }
 
 // ByteCountSI returns a human readable size from int64 bytes
-func ByteCountSI(b int64) string {
+func byteCountSI(b int64) string {
 	const unit = 1000
 	if b < unit {
 		return fmt.Sprintf("%dB", b)
@@ -299,9 +321,12 @@ func ByteCountSI(b int64) string {
 }
 
 // IsGIFAnimated will return an error if the GIF file has more than 1 frame
-func IsGIFAnimated(gifFile string) error {
+func isGIFAnimated(gifFile string) error {
-	file, _ := os.Open(gifFile)
+	file, err := os.Open(gifFile)
-	defer file.Close()
+	if err != nil {
+		return fmt.Errorf("cannot open GIF file: %v", err)
+	}
+	defer func() { _ = file.Close() }()
 
 	g, err := gif.DecodeAll(file)
 	if err != nil {
@@ -313,5 +338,5 @@ func IsGIFAnimated(gifFile string) error {
 		return nil
 	}
 
-	return fmt.Errorf("Animated gif")
+	return fmt.Errorf("cannot optimize an animated gif")
 }

main.go

@@ -1,3 +1,4 @@
+// Package main is the main application
 package main
 
 import (
@@ -5,9 +6,11 @@ import (
 	"os"
 	"os/exec"
 	"regexp"
+	"runtime"
 	"strconv"
+	"sync"
 
-	"github.com/axllent/ghru"
+	"github.com/axllent/ghru/v2"
 	"github.com/spf13/pflag"
 )
 
@@ -22,7 +25,16 @@ var (
 	optipng          string
 	pngquant         string
 	gifsicle         string
+	copyExif         bool
+	threads          = 1
 	version          = "dev"
+	// ghruConf is the configuration for the ghru package
+	ghruConf = ghru.Config{
+		Repo:           "axllent/goptimize",
+		ArchiveName:    "goptimize-{{.OS}}-{{.Arch}}",
+		BinaryName:     "goptimize",
+		CurrentVersion: version,
+	}
 )
 
 func main() {
@@ -42,24 +54,26 @@ func main() {
 		fmt.Printf("  %s -o out/ -q 90 -m 1600x1600 *.jpg\n", os.Args[0])
 
 		fmt.Println("\nDetected optimizers:")
-		if err := displayDelectedOptimizer("jpegtran ", jpegtran); err != nil {
+		if err := displayDetectedOptimizer("jpegtran ", jpegtran); err != nil {
-			displayDelectedOptimizer("jpegoptim", jpegoptim)
+			_ = displayDetectedOptimizer("jpegoptim", jpegoptim)
 		}
-		displayDelectedOptimizer("optipng  ", optipng)
+		_ = displayDetectedOptimizer("optipng  ", optipng)
-		displayDelectedOptimizer("pngquant ", pngquant)
+		_ = displayDetectedOptimizer("pngquant ", pngquant)
-		displayDelectedOptimizer("gifsicle ", gifsicle)
+		_ = displayDetectedOptimizer("gifsicle ", gifsicle)
 	}
 
 	var maxSizes string
-	var update, showversion, showhelp bool
+	var multiThreaded, update, showVersion, showHelp bool
 
 	flag.IntVarP(&quality, "quality", "q", 75, "quality, JPEG only")
 	flag.StringVarP(&maxSizes, "max", "m", "", "downscale to a maximum width & height in pixels (<width>x<height>)")
 	flag.StringVarP(&outputDir, "out", "o", "", "output directory (default overwrites original)")
 	flag.BoolVarP(&preserveModTimes, "preserve", "p", true, "preserve file modification times")
+	flag.BoolVarP(&copyExif, "exif", "e", false, "copy exif data")
 	flag.BoolVarP(&update, "update", "u", false, "update to latest release")
-	flag.BoolVarP(&showversion, "version", "v", false, "show version number")
+	flag.BoolVarP(&multiThreaded, "threaded", "t", false, "run multi-threaded (use all CPU cores)")
-	flag.BoolVarP(&showhelp, "help", "h", false, "show help")
+	flag.BoolVarP(&showVersion, "version", "v", false, "show version number")
+	flag.BoolVarP(&showHelp, "help", "h", false, "show help")
 
 	// third-party optimizers
 	flag.StringVar(&jpegtran, "jpegtran", "jpegtran", "jpegtran binary")
@@ -71,7 +85,9 @@ func main() {
 	flag.SortFlags = false
 
 	// parse args excluding os.Args[0]
-	flag.Parse(os.Args[1:])
+	if err := flag.Parse(os.Args[1:]); err != nil {
+		fmt.Printf("Error parsing flags: %s\n", err.Error())
+	}
 
 	// detect optimizer paths
 	gifsicle, _ = exec.LookPath(gifsicle)
@@ -80,28 +96,44 @@ func main() {
 	optipng, _ = exec.LookPath(optipng)
 	pngquant, _ = exec.LookPath(pngquant)
 
-	if showhelp {
+	if showHelp {
 		flag.Usage()
 		os.Exit(1)
 	}
 
-	if showversion {
+	if showVersion {
-		fmt.Println(fmt.Sprintf("Version: %s", version))
+		fmt.Printf("Version: %s\n", version)
-		latest, _, _, err := ghru.Latest("axllent/goptimize", "goptimize")
+
-		if err == nil && ghru.GreaterThan(latest, version) {
+		release, err := ghruConf.Latest()
-			fmt.Printf("Update available: %s\nRun `%s -u` to update.\n", latest, os.Args[0])
+		if err != nil {
+			fmt.Printf("Error getting latest release: %s\n", err.Error())
+			os.Exit(1)
 		}
-		return
+
+		// The latest version is the same version
+		if release.Tag == version {
+			os.Exit(0)
+		}
+
+		// A newer release is available
+		fmt.Printf(
+			"Update available: %s\nRun `%s -u` to update (requires read/write access to install directory).\n",
+			release.Tag,
+			os.Args[0],
+		)
+		os.Exit(0)
 	}
 
 	if update {
-		rel, err := ghru.Update("axllent/goptimize", "goptimize", version)
+		// Update the app
+		rel, err := ghruConf.SelfUpdate()
 		if err != nil {
-			fmt.Println(err)
+			fmt.Println(err.Error())
 			os.Exit(1)
 		}
-		fmt.Printf("Updated %s to version %s\n", os.Args[0], rel)
+
-		return
+		fmt.Printf("Updated %s to version %s\n", os.Args[0], rel.Tag)
+		os.Exit(0)
 	}
 
 	if len(flag.Args()) < 1 {
@@ -137,13 +169,38 @@ func main() {
 		}
 	}
 
-	for _, img := range args {
+	if multiThreaded {
-		Goptimize(img)
+		threads = runtime.NumCPU()
 	}
+
+	processChan := make(chan string)
+
+	wg := &sync.WaitGroup{} // Signal to main goroutine that worker goroutines are working/done working
+	wg.Add(threads)
+
+	for i := 0; i < threads; i++ {
+		go func() {
+			for nextFile := range processChan {
+				goptimize(nextFile)
+			}
+			// Channel was closed, so we finished this goroutine.
+			wg.Done() // Let main goroutine know we are done.
+		}()
+	}
+
+	for _, img := range args {
+		processChan <- img
+	}
+
+	// Close the channel.  This tells the worker goroutines that they can be done.
+	close(processChan)
+
+	// Wait for all worker goroutines to finish processing the IPs
+	wg.Wait()
 }
 
-// displayDelectedOptimizer prints whether the optimizer was found
+// displayDetectedOptimizer prints whether the optimizer was found
-func displayDelectedOptimizer(name, bin string) error {
+func displayDetectedOptimizer(name, bin string) error {
 	exe, err := exec.LookPath(bin)
 	if err != nil {
 		return err