ImageOptim is a free app that makes images take up less disk space and load faster, without sacrificing quality. It optimizes compression parameters, removes junk metadata and unnecessary color profiles.

ImageOptim seamlessly integrates the best optimization tools: PNGOUT, Zopfli, Pngcrush, AdvPNG, extended OptiPNG, JpegOptim, MozJPEG (jpegtran & jpegrescan), and Gifsicle.

It's excellent for publishing images on the Web (easily shrinks images “Saved for Web” in Photoshop) and also useful for making Mac and iPhone/iPad applications smaller (if you configure Xcode).

How to use it

Drag'n'drop images or folders into the window! The files will be optimized in-place (they're saved automatically). Detailed installation and usage instructions.

You can also drop files on ImageOptim's Dock icon, or use Services menu in Finder, or launch it from a command-line/shell script.

More about PNG

My article “PNG that works” explains why ImageOptim removes gamma information and how to get even smaller PNG files with transparency that works in ancient versions of IE.

Open Source

ImageOptim is free, open-source software under terms of the GPL v2 or later. You can find the source code on GitHub and improve it! Feel free to for assistance.

ImageOptim is sponsored by PSW GROUP. If you need an SSL certificate they have a special discount for ImageOptim users! Use code IMAOPT10.

PNGOUT is bundled with permission of Ardfry Imaging, LLC and is not covered by the GPL.

Frequent answers

How does ImageOptim compare to TinyPNG and JPEGMini?

Tools like ImageAlpha/pngquant/TinyPNG/JPEGMini/MozJPEG can make files much smaller by using lossy compression which (slightly) lowers image quality. ImageOptim is lossless — it compresses image files without changing pixels.

For best results use both, but the order is very important: first compress images using some lossy tool and then apply ImageOptim for even better compression.

Can I keep embedded copyright, camera information?
Yes. Uncheck Strip JPEG metadata in Preferences.
How to make ImageOptim faster on underpowered laptops?
In preferences uncheck PNGOUT and Zopfli. Without these options optimization will run quicker, but will be less effective.
Will ImageOptim be in the App Store?

No, and please beware of knock-offs in the App Store! Apple's has been selling two already.

ImageOptim is given for free on terms that basically say “you can do whatever you want except taking this freedom away from others”. Apple does not allow such permissive terms. Apple requires all App Store users to accept DRM (copy protection) and legal restrictions in the iTunes EULA.

You can get ImageOptim here, DRM-free. Its license allows you to share it, modify it, use it in any country in the world—even sell it—if you don't forbid anybody else from doing the same.

You can donate to support the project.