On the mac, ImageOptim optimizes SVGs, JPEGs, PNGs, and even animated GIFs. - Source: Reddit / 29 days ago
ImageOptim for batch processing is pretty good, assuming you'll be optimizing before uploading or using them. Comes as a mac app, or as a web service. - Source: Reddit / 21 days ago
Https://imageoptim.com/mac is a good, free alternative to Optimage. I concur, the others are good programs. - Source: Reddit / 18 days ago
For web, I just export at the final output size I want with quality cranked to 100 then run through https://imageoptim.com/mac. - Source: Reddit / 16 days ago
XnConvert - XnConvert is an easy image converter for graphic files, photos and images available on Windows...
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.
pngquant - command-line utility and library for lossy compression of PNG images
Phatch - Phatch = Photo & Batch!
CodeKit - CodeKit allows you to optimize the performance of your website by automatically and efficiently compiling a variety of popular languages.