This is a front-end for open source tools: OptiPNG, pngcrush, advpng, jpegtran and jpegoptim.
Images are made smaller (in terms of disk size) by recompressing them using best combination of compression settings, bettter algorithms, and by removing optional, invisible information like comments.
ImageOptim takes advantage of multi-core and 64-bit CPUs.
What's new in this version:
- Double-click reveals files in Finder
- Stability fix