Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
WebUtils Image Compress - Compress or convert images on the web with offline support. Images are not uploaded on server and processed on client with webassembly. Support for formats like JPEG, PNG, WebP, AVIF and JXL
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats
BIMP - With BIMP you can apply a set of manipulations to an entire group of images!