While I know 5 years cannot be much, it's a long time for me. I started using GIMP shortly after Sid Meier's Railroads! came out and have been creating and editing materials for the game ever since. I have over 30 Gig of hard drive space for SMR and close to half of it is in the form of DDS, TGA and a few other types of files done on GIMP. I'm not totally versed in GIMP, but I'm always learning more.