Several times I have seen techniques in PhotoShop that use brush dynamics to taper a stroke. Unfortunately GIMP doesn't have this capability (yet...but it is rumoured for 2.6) so I wrote a little script-fu to do it!
This is a re-post of a tutorial I made and hosted over at pbwiki before I had a web site...traffic there is down, so I am moving it to this site. Images like these would be used in making a battlemap, for VTT (or paper) gaming.
This tutorial will tech you how to take existing objects with a transparent background and making them look like gold metal in a relatively realistic manner.