ImageOptim Changelog


  • Much faster version of Zopfli (almost twice as fast)
  • Updated pngcrush, pngquant2, MozJPEG
  • Runs tools with lower priority (OS X 10.10+ only)
  • Updated Chinese localization (by pluwen)

This version requires at least Mac OS X 10.8 (Mountain Lion), and full functionality is only available in OS X 10.10 (Yosemite) or later.


  • Lossy GIF option. 50%-70% file size reduction!
  • Lossy conversion can be enabled permanently
  • Unified speed setting that controls all tools' compression/time trade-off
  • Romanian localization (thanks Oprea Nicolae)
  • Simplified Chinese localization (thanks asins)
  • Japanese localization updated (thanks KAMINO Aki)

This version requires at least Mac OS X 10.8 (Mountain Lion), and full functionality is only available in OS X 10.10 (Yosemite) or later.


This version requires Mac OS X 10.7 (Lion) or later, and full functionality is only available in OS X 10.10 (Yosemite).


  • Improved drag'n'drop of files outside ImageOptim window
  • Removed partial sandbox support that caused problems on some systems

This version requires Mac OS X 10.7 (Lion) or later. If you have older Mac OS X, please install the free system upgrade from Apple.


  • Option to Stop optimizations earlier (keeping progress made so far)
  • Removal of "Where from" OS X metadata
  • Lighter/faster default config on slow machines
  • Updated PngCrush, PNGOUT, ZopfliPNG
  • Autolayout used for the main window

ImageOptim 1.5.4

This is the last version that supports Mac OS X 10.6 (Snow Leopard)

  • Added Revert to Original option (restores unoptimized file)
  • Added cache of already-optimized files. In some cases ImageOptim will be able to quickly skip files it knows it can't optimize any further

1.5.4a6 (experimental)

1.5.3 (unstable)

  • Fixed compatibility with older Mac OS X
  • Fixed PNGOUT integration

1.5.2 (unstable)

  • Better compression on the first try due to improved management of temporary files and optimization parallelizm
  • Updated autoupdater
  • Improved Reveal in Finder
  • Fixed handling of relative paths when launched from CLI
  • Switched to newer APIs for path & file handling and simplified code for handling parallel queues


  • New: Copy as Data URL (copies small image files to clipboard as data:image/… URIs for easy inlining in CSS/HTML)
  • Less noisy output when run from command line
  • Updated translations for Russian, Czech, Danish, Greek, Italian, Japanese, Norwegian, Polish, Portugese, Turkish, Vietnamese and Chinese
  • Workaround for Code Signing problems (*shakes fist at Apple*)


  • Migrated to ARC memory management
  • Statusbar text with optimization result can be selected and copied
  • Lossy jpegoptim conversion (if enabled in Preferences) will be applied only if it gives >5% filesize gain
  • Updated Greek and Italian translations (thanks Giorgis Zacharakis and Oscar Fanelli)


  • New icon by Anna from icons8/VisualPharm! Crushed guy is now a magical press
  • Running from CLI directly is synchronous, hides the window and automatically quits when done:
    /Applications/ ~/Desktop/image.png
  • Purchased 1-year Developer ID from Apple to avoid blocking of independent software in Mountain Lion and Mavericks
  • Improved QuickLook integration
  • Fixed ⌥-click on Again button


  • Running optimizations again is much faster by skipping tools that are known not to improve compression when run second time
  • Improved backup of files on Samba network drives (10.8+ only)
  • Improved dragging and copy&paste of files in the list
  • Improved time-limiting of PNGOUT and Zopfli
  • Ability to disable dock bounce with defaults write net.pornel.imageoptim BounceDock -bool false


  • Fixed opening from Dock and command-line
  • ImageOptim won't try to optimize non-writeable files
  • Better cleanup of temporary files
  • Updated translations and added new:
    • Vietnamese (thanks to Biz Over and Phan Anh)
    • Turkish (thanks to Ali Riza Esin)
    • Czech (thanks to "fri")


Big thanks to James Stout for contributing several improvements in this release!

  • Zopfli compressor
  • Icons for “Retina” display
  • ImageOptimize service in Finder's context menu. You can disable it or add a keyboard shortcut in Finder → Services → Services Preferences…
  • Removal of Resource Forks and hidden attributes that inflated file size in Finder
  • Original images are “backed up” to Trash
  • ImageOptim no longer tries to be clever with preservation EXIF markers and always strips them when told to
  • Translations
    • Translations are now done via Transifex website. You can sign up and help!
    • Korean translation (thanks to Byung Hoon Cho)
    • Chinese translation (thanks to Jason C. Huang)
    • Lithuanian translation and updated Russian translation (thanks to Aleksandr Jadov)
  • Updated Pngcrush to 1.7.66
  • AppleScript command for checking how many optimizations are running (for integration with ImageOptim-CLI)
  • Overall optimization gain shown when optimizing same file multiple times
  • Tools are run in order that maximizes utilization of multicore CPUs


  • Added configurable columns (right-click table headers)
  • Status bar shows overall savings
  • Slowest settings are not used for very large files to avoid optimisation taking “forever”
  • Less aggressive optimization of GIF files to avoid bugs in Safari
  • British localisation
  • EXIF and color profiles are never stripped from large JPEG files (i.e. usually photos form digital cameras)


  • Included PNGOUT by default. Now ImageOptim includes all best optimisation tools out of the box!
  • Simplified preferences: options for stripping PNG chunks and JPEG EXIF data are in one place
  • Localization fixes by Gildas Lormeau
  • View Source option — because not only web apps have viewable source code :)


  • Removed troublesome optimisation from jpegrescan
  • Fixed jpegtran ran without jpegrescan
  • Updated Pngcrush to 1.7.22


  • Disabled jpegrescan due to compatibility problems
  • Updated Gifsicle to 1.64
  • Updated Pngcrush to 1.7.18
  • Fixed bug that could cause corruption of GIF files


  • Extended jpegtran optimisation with jpegrescan script by Loren Merritt
  • Norwegian Bokmål localization (thanks to Henrik Helmers)
  • Portuguese Brasil localization (thanks to Luiz Menezes)
  • Updated Gifsicle to 1.63
  • Fixed revealing of multiple files in Finder


  • Placeholder for drag'n'drop area
  • Running tools are immediately stopped when corresponding files are removed from the list
  • ⌥-clickOptimize again” to optimize only files that have previously been optimized successfully
  • ⌥-clickDelete” menu option to remove completed files
  • ⌘⌫ as well as and remove files from the list
  • File sizes are formatted according to system locale
  • Fixed Pngcrush integration freezing on some machines
  • Fixed Spanish localization


Major improvements in this release have been done by Reinhard Möller. Big thanks!

  • QuickLook integration
  • Added ability to copy, paste and drag files out of ImageOptim's window
  • Button to reveal files in Finder
  • UI improvements for OS X Lion
  • Fixed updating of file paths in preferences
  • Danish localization (thanks to Rasmus Kjær)
  • Spanish localization (thanks to Ben Pollard and Wayne Hartman)


  • Cosmetic UI fixes for OS X Lion
  • Dropped support for PowerPC
  • Dropped support for Mac OS X 10.5 Leopard. Snow Leopard or Lion is required

ImageOptim 1.2.5

This is the last version that supports Mac OS X 10.5 (Leopard) and PowerPC.

  • European Portugese localization (thanks to Sérgio Miranda)
  • Russian localization (thanks to Nicom)
  • Updated to Gifsicle 1.60
  • Updated to OptiPNG to 0.6.4
  • Updated to Pngcrush to 1.7.12


  • Italian localization (thanks to Fabio Sanna)
  • German localization (thanks to Alexander Mayer)
  • Updated versions of Gifsicle and OptiPNG
  • Fixed saving of AdvPNG-optimized images


  • Changed UI to match Leopard aesthetics (based on design by Martin Andersson from Auforia and Chris Messina)
  • Added Dutch localization by Mathias Bynens
  • Status column is sortable
  • Write errors are now properly reported
  • 64-bit and Snow Leopard compatibility improved

Current version of ImageOptim requires Mac OS X 10.5.8 or newer. If you have older system you should either update it or use older version of ImageOptim.


  • Added French localization by Mathias Richter
  • Added modified version of optipng that clears dirty alpha transparency (RGB components of fully transparent pixels)
  • Added Gifsicle for optimisation of animated GIF files (use PNG instead of static GIFs!)
  • Added tools menu for quick disabling/enabling of tools used


  • Fixed progress indicator
  • Updated Polish translation


  • Leaner and more stable thanks to new Leopard APIs
  • Can handle order of magnitude more files at once
  • Avoids writing many files to disk at the same time
  • Checks actual file type rather than rely on filename extension
  • PNGOUT may be gracefully stopped if takes too much time to optimize
  • Temporary files are cleaned up on exit
  • Errors during optimisations don't slow down or lock up ImageOptim

ImageOptim 1.0.10

This is the last version that supports Mac OS X Tiger.

ImageOptim 1.0.8

This is the last version that supports Mac OS X Panther.