Originally Posted by FunkeXMix
Hey thanks for the info, but I do not think the media queries method will work with eBooks because the file size will be to big if I need to have two copies of the same image in different resolutions.
Probably true. It just depends on how badly the artifacts on certain readers annoy you.
On the other hand, now that I think about it, you should probably start with a different EPUB doc for Kindle anyway, because if the file sizes are too big, kindlegen recompresses the images with a lower quality setting. So regrettably, the answer on Kindle is probably "ship the low-res version".