Image size & camera shake.
 

I guess I already know the answer to this question but I just want to make sure.

If I want to have an animation at 640x480 for example, and I want to use a camera shake effect like in After FX or some other compositor, then that means that I have to render the image sequence larger than 640x480 to make sure that the animation stays without any weird cutting, right?

Yep:)

It was a good idea to post this though, because maybe others were confused about this same issue:)

Yeah i was wondering about this myself a few months back. In the end I just did the camera shake myself in maya with a few keyframes and the trax editor :)