is there any way to prevent upscaling? (Aspect Ratio)



so my album cover images are often of different sizes.
i'd like to display them as big as possible on the NowPlaying screen, but for images that are smaller than the box i'd like them to not scale up.
the "center" value seems the best idea, but if the image is larger than the box it will be cropped...

you can do this in html/css (auto/maxwidth/maxheight), is there something similar for skins?