How do you get someone to back off without being too rude or blunt?

Some guy lately has been pissing me off. I’ve been (what I think is) very obvious in sending signals that I’m not interested. I ignore him a lot, I don’t reciprocate his flirty comments, and I’m generally pretty stand-offish. However, he’s not taking the hint and is practically smothering me. (I just got a text consisting of a picture of him and the words “Lol i have forgotten how fluffy and golden my hair is when i wash it haha :P Look how fluffy it is! :D” ....HELP ME, FLUTHER.
I don’t want to hurt his feelings but I want him to leave me aloneee.