There's a browser extension called Adblock Plus which detects and removes ads from web pages.
A neat hack is to replace the images with something else -this has been done with Catblock, which replaces them with pictures of cute cats.
In the 80s classic action move They Live, the protagonist gets some high-tech sunglasses which allow him to see the world as it really is:
Today marks the 2nd April 1st in a row that I've failed to get around to implementing the idea, so I throw it out there to the world in the hope that someone else will do the hard work for me and I'll be able to use it in my browser. Good luck!