April fools is coming up. I'd like to play this prank where we use an http proxy to modify images as they come through the proxy. I've been told that there are scripts/add-ons to ISA/Squid that can do this but I haven't been able to find much on my own.
Ideally, we'd like to superimpose another image on top of every .gif/.jpeg/.png that comes through the proxy. The only problem is I have no idea how to do this!
If I had my choice I'd rather do it with ISA than Squid, but beggars can't be choosers. If you can think of another way I'm open to that too!
Look here: The Upside-Down-Ternet ;)
You would need to replace the call in the script to add your additional image. ImageMagick would be a good tool for that.