You can't just replace that class animation with just anything, but if you did what this post in original about plus what I posted above to put a static pic anywhere you want you could put it over the animation and move the animation off the screen. There are several ways you can do it.
Another way is to just make another animation to replace it like I did. Each class has 1 to 3 graphic files that would need to be replaced if you wanted to do this....for instance a monk has:
monk01.tga
monk02.tga
Both would have to be replaced in order for it to work or else you'd have to know how to make it so one didn't show up. Which is a bit involved
Here's some links to what I did:
My graphic is simply a guild logo and this is what both my monk files look like since all my logo does is twinkle it's easy to adapt for just 1 file or if 3 are needed.
The Graphic I replaced my Class Animations with
It looks sort of like this gif animation but better since gifs only have 256 colors in it:
Guild Logo to replace my class animation
Here it is in my UI
Hope this helps!