Burning Down

Download Adblock Plus for free: Adblock Plus — for annoyance-free web surfing. The most common "subscription" is called Fanboy's List (English).

Right click the image, then at the very bottom of the menu that pops up there will be an option that says "Adblock: Block Image". Click it. Then in the box that pops up, just click "Add Filter" at the bottom. Voila! It will block the image's URL.

Adblock is also great to block annoying or flashy advertisements on other webpages. Just follow the same instructions.

Once an image is blocked, it won't show up again until you overturn the block in the settings. Also, if you install Adblock on Firefox, a little red stop sign will appear at the bottom left of the window. This probably happens on all browsers, but I'm not sure where they show up. When you click on the stop sign, you can open Preferences, etc.