I only check screenshots if i see a dodgy score or see signs of someone aimbotting etc.
I check their stats on bf3stats.com then check several screenshots. I then make my decision based on those things. If all their screenshots come back black though then i normally ban.
99.9% of screenshots always come through since i started using pbbans reccomended screenshot settings.
I'm sure my method is not perfect, but it seems to go down well with my regulars and i never have many complaints about hackers on the server.
Yep, thats what ive found. Thats how i spot a cheater on my server now, black screenshots. All the legite players work ok, just the cheaters that dont show up.