Crunch : Crunch is a tool for lossy PNG image file optimization. It combines selective bit depth, color type, and color palette reduction with zopfli DEFLATE c...
Squoosh : Squoosh is an image compression web app that allows you to dive into the advanced options provided by various image compressors.
PunyPNG : PunyPNG is a free website optimization tool that dramatically reduces the file size of your images without any loss of quality.
JPGCrunk : jpgcrunk is a tool for crunking images.
rsizr : rsizr is a Flash application that lets you resize JPG, PNG, and GIF images on your computer. With rsizr, in addition to normal image rescaling and cro...
Trimage is a cross-platform GUI and command-line interface to optimize image files via optipng, pngcrush, advpng and jpegoptim