Curtail (previously ImCompressor) is an useful image compressor, supporting PNG and JPEG file types. …
Trimage
Trimage is a cross-platform GUI and command-line interface to optimize image files for websites, using optipng, pngcrush, advpng and jpegoptim, depending on the filetype (currently, PNG and JPG files are supported). It was inspired by imageoptim. All image files are losslessy compressed on the highest available compression levels, and EXIF and other metadata is removed. Trimage gives you various input functions to fit your own workflow: A regular file dialog, dragging and dropping and various command line options. …