Probably trying to impress you that other girls find him attractive and want to be around him.
Its making you unhappy already, Poor guy doesn't realize it could all backfire on him and drive you away.
Help, I'm talking to the nicest guy in the world!! We've met twice but he is sending me pics of him with girls... I don't know what that means :( help me please I like him so much and he likes me?
If he's not telling you who the girls are ... Why he's having his picture taken with them ... Or why he's sending you the pictures - - sorry, but he is NOT "the nicest guy in the world".
And it's likely he doesn't really like you ... Or he would consider your feelings and tell you all that information.
He may or may not be trying to make you jealous. In fact it could be a way of him wanting to know if you like him much, by seeing how you react.
But then again don't be too worried, those girls could be his close friends! Nothing to it.
Good luck! (: