[Tim Wood]

If you have a single bitmap image, the only benefit would be if that image is large (and you have some way to load subrects w/o loading the whole thing) or if you are going to zoom in for some reason. Most of the memory savings of tiling is going to be irrelevant if you've already loaded the complete image.

In the cases we use this for, the reseting of the scale factor to 1.0 (at the end of a zoom operation) means that we maintain a 1:1 user coordinate to pixel mapping when we regenerate our tiles. So, text, shapes and lines get bigger without aliasing. If you have a bitmap image, you might get some benefit from this if you want to see sharp lines between source pixels instead of some sort of blurred bilinear filtering, but that's about it.