Lets turn that around and ask why would you care?
Assuming it's to determine if image/icon size is an issue, I've recently tossed all the multiple-resolution icons and replaced them with SVG graphics. Logos and larger non-vector images are all 2x size in a plain <img> tag.
Positive side effects are faster loads (the SVG is in the main style sheet) and easier modification. Haven't encountered any negative side effects yet.
If IE8 compatibility is required I will run one sprite file - make one page with all your icons and you can just screencapture it for instant sprites.