Ashampoo® Photo Optimizer - Ashampoo Photo Optimizer 8 enhances your photos at the click of a button! The program fully automatically adjusts colors, contrasts and exposure settings to perfection for individual images or entire collections.
ImageKit.io - Instant multi-platform image optimization
TinyPNG - Make your website faster and save bandwidth. TinyPNG optimizes your PNG images by 50-80% while preserving full transparency!
Resizing.app - Image resizing has never been so simple with free online resizing.app. Convert, optimize, resize images with ease and for absolutely free.
iLoveIMG - iLoveIMG is one of most powerful solution that comes with all the major tool you cloud want to edit images in bulk.
Piio - Generates responsive images so you don't have to optimize