VIPS is a free image processing system. > Website > Download > Changelog > SCM…
Converseen is an easy to use image batch converter and thumbnail creator. It is an open source project written in C++ with the powerful Qt4 libraries. Thanks to the Magick++ image libraries it supports more than 100 image formats. You can convert and resize an unlimited number of images to any of the most popular formats: DPX, EXR, GIF, JPEG, JPEG-2000, PDF, PhotoCD, PNG, Postscript, SVG, and TIFF.
With Converseen you can save your time because it allows you to process more than one image with one mouse click!