Image Comparision

Hello,

I have a project to work on which requires me to compare a jpg/gif/bmp with a screen shot I take.

Here is the whole scoop.
We have to test our website against couple of Browsers. Earthlink,IE,Netscape,AOL,mozilla, msn etc. to see how long is it
taking to download the websites which we host.
first way I thought of using windows messaging, but I dont know if all these ISP will give there internal architecture for free. So
second way, is to compare the screen shot of the (AOL,IE,NETSCAPE etc's) browsers download rotator (which rotates at top-right side with a static bmp/jpg/gif every x milli-seconds.
How do I do it?
Because I will be running( executing or starting) these browsers from my VB program. and Minimize my vb application. Run my set of URLs which we host and try to compare these screen shots every x milli-secs.


Or do u recommend any other way?
Thanks