From time to time you need to edit images on mass. This may be as simple as converting from one image format to another or as complecated as performing many different actions on multiple files. If you are looking to a Linux Image Converter take a look at Phatch

Phatch is a simple to use cross-platform GUI Photo Batch Processor which handles all popular image formats and can duplicate (sub)folder hierarchies. Phatch can batch resize, rotate, apply perspective, shadows, rounded corners, … and more in minutes instead of hours or days if you do it manually. Phatch allows you to use EXIF and IPTC tags for renaming and data stamping. Phatch also supports a console version to batch photos on webservers.

http://photobatch.stani.be/