Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.

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.

ImBatch - ImBatch is a batch image processor with a nice graphical user interface.

Phatch - Phatch = Photo & Batch!

Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats

Namexif - Namexif is a free software to rename photos by date and time based on EXIF.