RIM didn't add the API (interface) required for developers to change the homescreen wallpaper until OS4.7. So unfortunately no. There is a sort of work around, it can be built into a theme using composer, the images and rotation times would he hard set, but it works.
First youll need to download the Theme Studio 5.0. Then in Composer youll import all the wallpapers you want to use (I dont think youll be able to do more than 10 or so due to size issues). Now I cant remember exactly how I did it, its been a while (did it a while back when I had an 8330), but I *think* what I did was in the time line set 1 image visible and the rest non visible, then a few minutes later switch the visible image. If you look in the theme developer forum here there are some guides that will get you started with Composer, because it can be a little confusing.
