Simple question... Say you have a part of a background image that is like 25 kb, a gradient or something, and you set it to repeat, how much bandwidth does it actually use? Does it only use 25 kb + the nominal amount of code used to set it to repeat or is there something I'm missing?
No. You are not missing anything. The background image would take exactly 25 kbytes plus the code overhead. We also use a gradient background on our site, which is about 500 bytes and that's what it actually takes bandwith-wise.