One downside that hasn't been mentioned so far, as far as I can tell: the conflict between caching and downloading unneeded image data. If you use image 1 on p

One downside that hasn't been mentioned so far, as far as I can tell: the conflict between caching and downloading unneeded image data. If you use image 1 on pages A & B and not page C, but image 2 on pages A & C but not B, you face a dilemma. - If you stuff it all in one big CSS file, visitors to B (C) will download image 2 (1), even though it's never shown. - If you split the CSS in 2, with A including both and B & C including only one each, you'll have an extra request in A, and require duplication or a third file if B & C share style rules - If each page serves its own CSS file, you have only 1 request but it (and the image data) won't be cached across pages. This restricts this technique to images that are used all over the place or images that are tiny.