A mint leaf traced with Inkscape from http://upload.wikimedia.org/wikipedia/commons/5/55/Koeh-095.jpg (by Koehler).
The image is very large!
-- Nicholas Paun
Magic words fits for any educational project, can also be used for bookstores, library or other. Under Creative Commons 3.0 Attribution Non-Commercial.
Planet Saturn Bitmap Trace. This was a challenge to get it to a small size. The Gimp was used to clean up, rescale and reduce colour. I Love Inskcape! The original public domain image can be found at http://upload.wikimedia.org/wikipedia/commons/e/e3/Saturn_from_Cassini_Orbiter_%282004-10-06%29.jpg