Piio - Generates responsive images so you don't have to optimize
PhotoPenguin App - PhotoPenguin is a completely free batch photo editor with support for cropping, resizing, adding watermarks, and converting photos to other formats. It works on the user's device, using the capabilities of modern browsers.
Imagify - Optimize and resize images online and through your CMS.
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats
Crunch - Crunch is a No Judgment Gym that believes in making serious exercise fun by fusing fitness and entertainment. Join Crunch for all your fitness needs!
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.