TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
GraphicConverter - Graphic Converter for Mac and Windows, can converts image formats BMP, JPG, GIF, ICO, PNG, TIF...
ImageOptim - Faster web pages and apps.
BatchPhoto - BatchPhoto is a batch photo editing software for Win and Mac that can convert, resize, annotate and watermark hundreds of photos in one go. Learn more and try it for Free!
TinyJPG - Compress JPEG images with perfect quality and file size
XnConvert - XnConvert is an easy image converter for graphic files, photos and images available on Windows...