Imagecompressor.io - Tool to compress jpeg & png images online.
ImageOptim - Faster web pages and apps.
Sirv - Dynamic image processing, hosting and rich-media for retailers and eCommerce.
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Ralpha Image Resizer - High-speed image batch conversion tool
Oxipng - Oxipng is a multithreaded lossless PNG compression optimizer. It can be used via a command-line interface or as a library in other Rust programs.