Deleted texts?

So I only go through my boyfriends phone when I feel he’s hiding something (only 2 times) and I know that makes me seem crazy but in his pics he has an accidental screenshot from a girl that we used to work w saying “you can” (and she’s been trying to get with him since before we even got together) and when I went to his texts she wasn’t there? The picture was from the 25th of February so it wasn’t that long ago either. What do I do?