[tekdemon]

I've noticed this on my phone as well-it seems to happen very noticeably in 6.5 at least on the rom I'm running. On 6.1 I also saw it use a blurry photo a couple of times but it would just start blurry and stay blurry.
I think it may have to do with the phone trying to save memory, since it seems to occur when there's a lot of people in favorites and/or there isn't a lot of free ram. I think there'z also some kind of size threshold where the phone will resize the pics because one of the placeholder "female" pics won't ever go blurry while one will every time.
I removed all my contacts except for 3 then reset the phone to clear up the memory and it seems to be holding the high rez pics for now. We'll see if it'll still go blurry if ram gets low enough.