Promo Instant Image Resizer - Automatically optimize images for web & social media (free!)
Squash 2 for Mac - The easiest way to compress and optimize images for the web
Responsive Image Breakpoint Generator - Turn one image into the ideal set of per-device images
Icecream Image Resizer - Image resizer by Icecream Apps is a program to resize images fast and free. Windows version. Free Download.
Placid - Use Placid to auto-generate images, videos & PDFs from reusable templates
Resizing.app - Image resizing has never been so simple with free online resizing.app. Convert, optimize, resize images with ease and for absolutely free.