Q: I was in NY testing with models with my buddy who got an agency to send us 3 models and I got another agency to send us 4 models. And so I took photos of his models from the other agency I don't know, and they just called me and asked if I can send them the hi-res pictures of their models because they love them and want to use them for portfolio.
I don't know if you've shot for agencies for testing with their models, but would you charge them? Or just hand them over since it's a "test"?
A: The answer is "It depends..." Because it's really all just a game.
If you say, "Pay up" you run the risk of offending the other agency and getting black listed. After all, you didn't have their permission to shoot their models and you took pictures anyway. Furthermore, unless you're a really famous photographer, chances are the agency has never heard of you so you have no clout or pull over them.
I would instead use this opportunity to form a relationship with said new agency and let this be an "introduction". Get to know the agent/agency and allow the conversation to flow into the requirements for paid testing (your ultimate goal). Find out what you need to do to become a paid tester and give them the opportunity to see what you can with these first pictures.
This gets the relationship off on the right foot and leaves the agency with a good impression of you. Win-win for everyone and hopefully they'll eventually let you shoot paid tests if you are good enough! :)