What are some alternatives?
When comparing pngquant and Optimus.io, you can also consider the following products
ImageOptim - Faster web pages and apps.
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
PNGGauntlet - -Combines PNGOUT, OptiPNG, and DeflOpt to create the smallest PNGs
JPEGmini - JPEGmini - The Photo Optimization Tool Trusted by Tens of Thousands Image Perfectionists
OptiPNG - OptiPNG is a command-line PNG optimizer that recompresses image files to a smaller size, without...
XnConvert - XnConvert is an easy image converter for graphic files, photos and images available on Windows...