I belong to the "snapshot" camp. When vacationing with friends, I would assume that photos would be shared. With digital cameras being the norm these days, it is so easy to take multiple shots (no need to worry about wasting film, or developing time). The OP admits that she is NOT a professional photographer and unless the OP was carting along special lights/reflectors and/or spending a long time setting up shots, how was the friend to know that she regarded her photos as "art" versus "snapshots"? I don't think the friend was rude for assuming that the vacation photos would be shared.
My best friend is a professional photographer, and she uses her good camera a lot even when she's shooting for fun. So just the fact that a professional style camera with equipment was being used does not mean that the photos would be off limits for general sharing. I've watched my friend work and there is a big difference in how she shoots fun vs. job. Job means a significant amount of work for set up and lighting, or several series of test shots to determine the best angles, natural lighting, etc. Fun means point and shoot, and picking out the best photos afterwards. It seems like the OP was shooting for fun, and was pleasantly surprised at the quality of some of her shots.
That being said, the OP does have the right to keep her photos to herself. But if she values the friendship, an explanation is needed.
I would not be upset if a friend refused to share all her vacation photos with me, but explained it was because she wanted to use the photos semi-professionally and would be willing to make me a photo book.
I would not be upset if the friend gave me photos, but made it a condition that I could not post them on any online site.
I would not be upset if the friend told me that she wanted a chance to look through all the photos first, edit them, etc. Then she would be able to give them to me or upload them to a photosharing site where I could download them.
I would be upset if I asked for vacation photos, and all I got was the ones of myself. Then, if I asked for the rest, I got nothing but bean-dip.