I had the same problem with an avatar. I tried to block it, but it blocked all the images on E!
Anyway, the solution is really simple. You don't need to go in and add a new block rule. All you do is right-click > Adblock Plus: Block image...
This screen will pop up. Select "custom." I used your avatar as an example of what it would look like. (Not that I would block yours. I love Rei.
And that's it! Only that specific image will be blocked. That's assuming you have the same version of ABP as I do. I think it's the latest.