You've set up a false dichotomy, I think. Why use high-res low-quality images instead of just sticking with low-res high-quality images? It's all going to loo

You've set up a false dichotomy, I think. Why use high-res low-quality images instead of just sticking with low-res high-quality images? It's all going to look fuzzy when you zoom in. Also, palette images should get some love too. A high-res dithered GIF or 8-bit PNG might meet your needs (looks good on retina displays at normal zoom, stays crisp when zoomed in, smallish file size) better than the other options.