At the start of S03E02, Wendy's brother freaks out after he sees a photo. Now, I'm not going nuts, right: the photo isn't revealed in that episode?
I'm not done the show yet, so no spoilers past season 3, episode 2, please.
It's never revealed exactly what the photo was. Likely a photo of the girl in some sort of sexually compromising situation. Nude selfies and the like. It's not a major plot point & the entire scene was meant to tell the audience about his character more than anything.
shareI guess I just assumed it was coming back like the pornograpic scene Marty was obsessed with in Season One came back for a pretty big reveal later.
That explanation makes sense, though.