I made a special minimun config for proxomitron.
Unzip and run it: http://www.mediafire.com/download/6dv4btgr5s6rbxo/prox.zip
For any software where you want to block some urls, set the proxy as localhost at the 8080 port
For MB, go to preferences, internet. Tick server and leave username and password blank
If prefer another port change it there, and go to Proxomitron\Configure\HTTP\Proxomitron's proxy port number
Restart MB, restart proxomitron if you changed the default port.
And that's all, now any time you see a pic you don't like. Go to http://127.0.0.1:9235/.pinfo/urls/
from your favourite browser, localize the pic you don't like and add it to the list redirections.
The redirections list is prepared for doing more complex things, but for this area is sufficient adding $SET(\1=http://local.ptron/removed.png) after the url you want to block.
For editing redirections list just use notepad or from proxomitron, right click in tray icon\edit list\redirections
Yep, complex and not very user friendly, and trust me, this is one of the easiest things in proxomitron... But nothing more can be done for this program as code got lost.
I blocked the image in http://imageshack.us/photo/my-images/46/nevershowagain.jpg/
as an example
The removed.png can be changed por any other like this one http://images2.wikia.nocookie.net/__cb20120614232753/meme/es/images/thumb/e/ed/IUGH-meme.jpg/500px-IUGH-meme.jpg
just save it as removed.png in the html folder of proxomitron
@Bee-liever: Don't feel pressed to use it, it hasn't been real work for me, just deleted all the other filters i use