This was my final achievement which I unlocked today and from my experience its not just badass's which drop the pictures. The other big guys do as well. I got the 10 at the bar room brawl tire 3 quest. I didn't actually activate or turn it in just went into the bar and started shooting. I was getting up to 3 per round compared to maybe one if I activated the quest. Also the pics are different and it took more than 10 for me to finally get the achievement so I'm guessing that because there is more than 1 type of picture they need to all be the same style. Just adding my 2 cents.