Personally I give each character a face, either from a person I know who matches their personality or a celebrity that fits the description, even though sometimes it can be really annoying if the author gives more details on the persons appearance and my character doesn’t fit that lol. I’m very curious as to what other people do.
I don’t see pictures in my brain at all. I read the words and understand the concept, so I know that the character is red haired, etc, but I don’t actually put a picture with the description.