ImageOptim is excellent for publishing images on the web (easily shrinks images “Saved for Web” in Photoshop). It's useful for making Mac and iPhone/iPad applications smaller (if you configure Xcode to allow better optimization).
OptiPNG is a command-line PNG optimizer that recompresses image files to a smaller size, without losing any information. This program also converts external formats (BMP, GIF, PNM and TIFF) to optimized PNG, and performs PNG integrity checks and corrections.
-Combines PNGOUT, OptiPNG, and DeflOpt to create the smallest PNGs -No image quality is lost — only file size -Converts JPG, GIF, TIFF, and BMP files to PNG -Ultra-configurable
PNGGauntlet is a .NET program that uses Ken Silvermans PNGOUT, OptiPNG and DeflOpt to optimize PNG fil.
JPEGmini is a patent-pending photo recompression technology, which significantly reduces the size of photographs without affecting their perceptual quality. The technology works in the domain of baseline JPEG, resulting in files that are fully compatible with any browser, photo...
Minuimus is a file optimizer utility script: You point it at a file, and it makes the file smaller without compromising the file contents.
Leanify is a lightweight lossless file minifier/optimizer. It removes unnecessary data (debug information, comments, metadata, etc.) and recompress the file to reduce file size. It will not reduce image quality at all.