Canva - Canva is a graphic-design platform with a drag-and-drop interface to create print or visual content while providing templates, images, and fonts. Canva makes graphic design more straightforward and accessible regardless of skill level.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Sketch - Professional digital design for Mac.
Ralpha Image Resizer - High-speed image batch conversion tool
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats