If you did that, it seems to me one image container for both front and CD covers would suffice. But it's the behaviour of the container that makes the difference. Whether it's used for covers or something else, the behaviour of displaying only a thumbnail in the skin—which can be double-clicked to display the full image in the viewer—is a reasonable one. On the other hand, some may want to display a larger version in the skin (e.g., resizing a cover in the skin, just as a poster is now). So if you were to change both these fields so they behave like posters, that would be fine (because the desired behaviour could be specified in the skin), but what about the issue of very large images slowing the drawing of the card?