Although I have no proof, I must agree that picture quality in my 920 seems to have went down dramatically. I got owned by a friend's S4 in normal conditions (yes my lens were clear). I'm no expert, but I seem to get a lot of noise in my pictures which didn't happen when I bought the phone. This actually makes me think twice before upgrading to a 1020 or its successor later this year, MS/NOKIA downgrading camera performance as time goes by? Maybe they want to let their flagships shine. Maybe it's because of developer preview, but I think I had this before. Anyway, if I get the same pictures with Cyan, I will really be disappointed.
[EDIT]: I really think it's a software issue, that is what annoys me the most.