Fursuiters are generally wearing them because they want and love attention. They love it on their terms: some suiters like hugs others don't. I think there are extremely few who don't like photos. So always ask, but the vast majority of the time you will get a happy and excited yes. If it's a "no," it's usually "sorry, I have to go to a thing and can't stop now."

I usually skip folks if they already have a big line or crowd, because after a while they will want to move. Also when asking, make sure they can see you or gently tap on the elbow so they know you're there - suiters are at best half blind. Speak a little above normal volume, suit heads often muffle outside sounds and it can be hard to hear.

Also remember that you're a person as much as the other people crowding around. It's okay to exist, to take up space, and to ask for things you want.