Open gl optimization (texture question)

Hey, thanks a lot for this, really good information. One last question, though. Reducing bith depth is the same as compressing the image right (say jpg for instance)? In the sense that it'll only be lower for archive sizes, but at runtime it'll need the same video memory because it is the same size (else, i can use a lot of palete reduction, as my maps are turning out quite monochromatic).

Thanks again :D