This is just making me feel worse :/
You just exposed a very personal picture that someone who trusted you, gave to you. Of course you should feel bad. Why the hell would you think that's okay? That's not acceptable. If I were Bubba I'd be pissed.
But I'm not saying bubba is totally right here, she put herself out there, she was just trusting you'd be mature enough not to show the pictures.
Protip for bubba, don't send anyone those pictures unless you know them IRL. You have no forgetin' idea who these people really are inside.