TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Imagify - Optimize and resize images online and through your CMS.
ImageOptim - Faster web pages and apps.
Cloudinary - Cloudinary is a cloud-based service for hosting videos and images designed specifically with the needs of web and mobile developers in mind.
TinyJPG - Compress JPEG images with perfect quality and file size
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.