Online Convert - Convert files like images, video, documents, audio and more to other formats with this free and fast online converter.
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Pixillion - Easily convert photos and images between file formats in a batch or single file. Compress, rotate, resize, or add text and watermarks to any file. Free download.
ImageOptim - Faster web pages and apps.
FileStar - With FileStar you can "do anything with any file".
TinyJPG - Compress JPEG images with perfect quality and file size