Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.
Resizing.app - Image resizing has never been so simple with free online resizing.app. Convert, optimize, resize images with ease and for absolutely free.
Shrink O'Matic - Shrink O'Matic is an AIR application to easily (batch) resize (shrink) images.
Image Resizer for Windows - Lets you resize images by right-clicking.
Tinuous - An image converter batch-processing multiple files. JPEG lossless transformations are implemented.
punchi.me - Edit one or several images in a few clics.