Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.
Pixelhunter.io - Free AI image resizing tool for social media
Shrink O'Matic - Shrink O'Matic is an AIR application to easily (batch) resize (shrink) images.
ImageKit.io - Instant multi-platform image optimization
Squash 2 for Mac - The easiest way to compress and optimize images for the web
Resizing.app - Image resizing has never been so simple with free online resizing.app. Convert, optimize, resize images with ease and for absolutely free.