I love this tool. I use it on every image I output for web, PowerPoint, etc.

ImageOptim provides GUI for various optimisation tools: AdvPNG from AdvanceCOMP, OptiPNG, Pngcrush, JpegOptim, jpegtran from libjpeg, Gifsicle and optionally PNGOUT.

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 applications smaller.

I’ve had some PNG and JPGs reduced dramatically —over 80% savings on some. On average, you’ll save about 30-40%.

Mac OS X only…