BRIC
BRIC is a powerful tool for batch image processing.
Bric is a cross-platform batch image processor. You can convert, resize, rotate and add watermark to your images. Multiple file types are supported for input and output.
The project started back in 2011 and was maintained for a couple of years. In 2020 BRIC is again in active development, so some of the features written below might be outdated. Please be patient, until everything is reviewed and rewritten.