I uploaded a replacement version of the left-hand image in my signature to Elluiki, replacing the current one. The image didn't change, either on the Elluiki image page (File:Flag_icon_bar.png) or in my signature. I uploaded again. Still no change.
Am I running afoul of some kind of caching, or do I need to do something more complex?
(If you see a "female" symbol inside the heart at the center of the leftmost flag, you're seeing the old version, like me; if there's no such symbol, just a heart, you're seeing the new version.)