No, it was named after the character, GIMP is a reverse acronym:

It took us a little while to come up with the name. We knew we wanted an image manipulation program like Photoshop, but the name IMP sounded wrong. We also tossed around XIMP (X Image Manipulation Program) following the rule of when in doubt prefix an X for X11 based programs. At the time, Pulp Fiction was the hot movie and a single word popped into my mind while we were tossing out name ideas. It only took a few more minutes to determine what the ‘G’ stood for.