PNGQuant – to strip unneeded chunks from PNGs. PNGQuant is a lossy compression library for PNG images. This library preserves a full alpha transparency.
JPEGOptim – provides lossless optimisation it is one of the most efficient library for JPG conversion among JpegTrans, mozjpeg and jpegrescan.
OptiPNG It’s a PNG reducer that’s used by lot of online optimisers.
Posted in: Image Compression