[odog]

From http://www.tweakxp.com

There are 2 bitmap images that IE uses for the logo in the upper right hand corner. One of them is 22x22 and the other is 38x38. To make an animated logo, you just need to know that each frame is stacked one on top of the other, with the first one being on top. The first 5 frames are run once, then frames 6 through X will be looped while the program is getting info.

So, to make an animated bitmap image of your own, just make each frame 22x22 (or 38x38) and cut and paste them into one BIG image that is 22x (Xframes times 22). Save the entire shebang as one .bmp file, and then get into group policy editor (either through powertoys or the run command) and set the image to your new custom one.

From group policy editor it is:

User Configuration -> Windows Settings -> Internet Explorer Maintenance -> Browser User Interface -> Custom Logo

Enjoy!

Link to this tweak below:
http://www.tweakxp.com/tweakxp/display.asp?id=1376