Congrats on using The Gimp! Together with Inkscape (for vector drawings) and MyPaint (for sketchings), it's one of my favorite tools!
Also, may I remind my fellow brewers that it's best to check first if images are copyrighted and/or free to use either personally or commercially, and if you can modify them, etc.
Wikimedia Commons has TONS of pretty images and paintings, which are either in the public domain, or under some sort of Creative Common license.
Oh, by the way here's a great plugin to create tileable textures:
The Texturize plugin for The GIMP
Anyway, happy label making!
