He is not finished so I won't show any more, but the banner is all done and I used an old Hieronymus Bosch painting (from about 1490) for his banner. Here's the original painting:
Here's the decal sheet, sized in Photoshop to 8.5x5.5. In the end I only used the top two of the bigger designs, the others didn't not print up well.
Here's the front of the banner...
here's the back..
It's not a typical Chaos banner with the usual symbols, but to me the original painting and the end result both wonderfully exemplify the world of Chaos. It's great fun making those banners. I did do some painting and washing over and around it to make it blend nicely.