Maximus-
Doesn't seem advanced so much as she is confused or hesitant.
Women have different tastes in women just like men do. Like, if you and your three best buddies compare notes on what girls you think are hottest, you'll notice that they think your 10s are just 7s and 8s, and their 10s are just 6s and 7s to you, and so on and so forth. Same deal with women.
What you want to do is try and figure out what kind of look she likes or, even better, figure out what kind of personality she meshes with well, and match a girl who goes with it. If she's dominant, she'll generally fare better with a woman who is soft and submissive, because she'll get a charge out of dominating her sexually and making her submit. If she's submissive, she'll more enjoy a dominant woman. etc. I've had dominant girlfriends I introduced to submissive girls saying things like, "I want to make her lick my pussy. I don't want to lick HER pussy, I just want her to lick MY pussy," and things like that, because that is how they start thinking when they're around women like that.
I'd stay away from showing pictures. Instead, I'd just tell your girl you're going to grab lunch or dinner with this other girl so she can evaluate her. Make sure you let YOUR girl know that the other girl thinks it's just a lunch and doesn't know there's any kind of sexual agenda (and don't tell the other girl there is, either). That way your girl can evaluate her without being worried about being judged or pressured.
You'll find that a girl that maybe she wouldn't have been impressed with looks-wise had she just seen her picture becomes a girl she'll be very excited about after meeting and getting to know in-person. Women aren't visual; they need story, personality, and romance.
In fact, rather than show her a picture, if you want to build up the anticipation, tell your girl some romantic stories you know about the girl you're about to meet before you meet her instead. Help her imagine.
Chase