Ralpha Image Resizer - High-speed image batch conversion tool
Image Converter Plus - Image Converter Plus is a multifunctional conversion and resizing tool for Windows operating system.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.
FileStar - With FileStar you can "do anything with any file".
PhotoBulk - PhotoBulk is a bulk image editor for Mac that was created for the best experience of batch editing. With this image editing software for macOS you can add watermarks, optimize and resize pictures, convert images or rename photos in bulk.