I've always liked the initial seconds of this video of Jodi Boam getting ready to pose precisely because of that: her upper torso actually gets bigger as she tenses her lats.
Anastasia Leonova has plenty of these impressive "Lats Deployment" videos - there was one I couldn't find of her tensing one at the time.
This "growing" effect looks 10x better in slimmer bodies, like Vanessa Serros' here.
In this thread, post any videos or images where it looks like a girl’s muscles are growing bigger or they are growing taller or both.