You can import SVG (Scalable Vector Graphics) into your GIMP Images through a menu found in the <Paths> Dialog.
You can get SVG from a few places; Open Clip Art is one source for free SVG. GIMP source has a Wilber SVG (made by Simon Budig) that was included in the Wilber Paths to Stars tutorial here at carol.gimp.org and also a new Wilber2 SVG created by Patrick Hulin using Inkscape and donated via an enhancement bug report.
If you load the Wilber2.svg into Inkscape, it will draw a beautiful Wilber complete with his construction hat. Inkscape is made to draw vector art and it does this task well and GIMP makes pixel art, so when you import the SVG into a GIMP image, it adds the paths to your image and allows you to conduct path manipulation on pixels with it.
Here is the dialog that you get when you request from the menu to import an SVG. This dialog is built from a gtk+ => gtk+-2.8.6.
The dialog is nice in that it will only display files that have the .svg extension by default.
After you tell the dialog to [Open] an SVG into the image, you can see the newly imported
paths in the Path Dialog. Here is what it looked like when I started to make the image for the Wilber Stars Tutorial.
You also might find the python script paths.py useful for manipulating images in GIMP which contain many paths like both of the wilber SVG.