ResizePixel - Free image editor to crop, resize, flip, rotate and convert images online
Ralpha Image Resizer - High-speed image batch conversion tool
Bulk Resize Photos - Resize large photos in bulk
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
PQINA Photo Editor - A free, fast, mobile-friendly, online photo editor to quickly edit pictures.
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.