Yeah there're a few scenes with conditions to unlock, can you tell me their positions on the gallery page? Like 'the second one of the first row', etc...
Unfortunately all of these need you to replay the game if you don't have the save file at the correct point.
The Ochaco ones, you unlock by bringing Ochaco into the cave lab with you during Mei's quest. It's weird that you unlocked the Tsuyu scene there but not Ochaco, lol.
For Tsuyu, the answer is in my previous post.