Well, the problem existed long before army banners existed. When rulers submit new banners for realms, or the associated avatar, the submitted filename is used. That's how I noticed the issue first, a few years ago. Some realm's icon wasn't showing up. I talked to someone else about it, and they said it was just fine. A bit of digging around revealed that AdBlock was blocking the image. So I whitelisted the whole domain.
Army banners are actually not uploaded by the devs. The banner is designed by the army sponsor and saved as a text string. The image is dynamically generated by the game when the page is loaded. So there is no image uploaded by anyone. I suppose Tim could change the image name, but that wouldn't solve all your problems anyway. The next time someone submits "banner.png" as their realm banner, AdBlock+ will ever-so-thoughtfully block it so you don't have to see that evil banner ad.
So to really fix the problem once and for all, just whitelist the domain. It'll probably make your pages load faster anyway.
