Thought this might be of interest to collectors...autographed Dredd photos can be purchased from Official Pix's website. Not particularly cheap though...
http://www.officialpix.com/estore/products.asp?cat=94&pg=3
(http://www.officialpix.com/estore/prodimages/sc0003.jpg)
pretty sure this is the same company that was selling photos for signings at the Dallas con I went to. The photos themselves aren't really that great quality...sometimes they are just blown up from screenshots. Just a a fair warning.
Karl is doing quite a tour around the world this year at cons, if you're lucky enough to catch him at one.