I’ve been frustrated for a while (after swapping to the Iconic One theme) with some images appearing blurred. For most websites this wouldn’t be much of an issue, but since I post art it was causing me no end of headaches.
After some less than useful Googling and research into the zoom and resize tags I finally figured it out!
Rassum-frassum Jetpack Photon! (“Speed up images and photos.” HA.)
Apparently that was also the reason that some of my images showed up broken every so often. That’s on me for not paying more attention to what it really was and all its known issues before I turned it on… but RAR!
So I turned that off and it looks like that was enough to clean things up.
TL;DR: If you are seeing blurry images on a WordPress page and the images look just fine in the Edit Post screen… Photon is why!