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:
- 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)