The program supports many different picture formats from the most known ones like jpg or gif to other rare ones like uncompressed RAW.
Apply layers, edit them and the, import them with GIMP to continue edition tasks.
Batch photo edition is a curious option that will allow you to edit many photos at once. Apply filter, change format or resize several pictures in one click.
Photivo is an interesting photo edition application that, when combined with GIMP gets even better and takes this latest one to a further level.