Most Helpful Guy
Hang on a second. He is a shy guy, but has lots of girls liking his pictures on instagram and has a lot crushing on him? That doesn't square up if you ask me. I would say shy guys in general won't get that many girls liking their pictures on instagram, nor know many girls at all. Nontheless like others have said just message him, don't worry about coming across badly. You can even say you like him so much that you had a friend give you his snapchat. If he likes you he will talk to you, if not then it will just be the same as saying hi on the street.
Be warned though, if this guy has a lot of female attention he may fall into the category of not wanting anything more than sex, or already being involved with one, or if not more woman. Not saying he is like that, but I know a lot of vein guys who are constantly fed attention from girls and sometimes this can make them that way.