I'd like to respond to everyone's posts, but that's a bit unmanageable at this point. Many thanks for the comments, everyone. We sorted things out yesterday. She demanded that I delete every messenger conversation I've ever had with Sarah and rip up any picture I owned with her in there (though she allowed me to just cut out certain portions for photographs I really cared for), but all things considered that's not such a bad punishment - when I have the only girl I care about back, what else really matters? I know perfectly well not to do anything like this again, though. What a headache this whole episode was. She made me apologize so many times that I think my voice box is sore.
I would be very glad that she decided to forget!
And you had pictures of that girl? I understand that part, if my bf would have picstures of other girls on his comp I would kill him. But well she went a little far on the chats, but it was just to make sure ^^

Glad everything sorted out