Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.
ezgif.com - Ezgif.com is simple online gif maker and toolset for basic animated gif editing.
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
Instagiffer - Create GIFs from anything!
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Gifox - Delightful GIF Recording and Sharing App for macOS