Most Helpful Girl
It depends on how old they were when they lost their sight.
If they were always blind, they don't dream in pictures because they have never seen any images. They dream in sounds and smells and feelings.
If they lost their sight later in life, they may dream in fragmented images but it will be predominantly sounds, smells and feelings.0
Most Helpful Guy
I am practically completely blind and I can tell you that both of these are the case. So yes.
First of all: all more or less intelligent life forms dream. Not only humans but dogs and cats and apes and probably other smart animals such as dolphins. In dogs and cats, this can even be experienced as an outside-spectator sometimes (for example dogs move their legs etc.). We don't know in detail how animals dream but it is pretty safe to assume that they have similar dreams to us human beings.
As for blind people seeing their dreams:
Until quite recently, people (including scientists) believed that blind people do dream but that "obviously" they can't see their dreams. Instead of seeing things in their dreams, their brains would work with the audio and other sensory experiences that blind people have during the day.
However, this is not true. I am (almost) blind since birth and I do see things in my dreams. It is true that generally speaking, all the other senses (especially hearing and touching) are more prevalent in my dreams but I also see things. In fact, a very recent research from German psychologists in 2014 found that when a group of people who are all blind since birth were asked to talk about their dreams, almost every single one of them said that they can also see things in their dreams. Even more surprisingly for people with good eyes, these blind people were even able to draw the things on paper that they had seen in their dreams (well enough that it was possible for the psychologists to guess what it is).
The reason for this is quite simply. While people like me might not exactly "see" things, we still know what they look like. When a blind person touches, say, a typewriter, he/she can still imagine what the thing looks like. Furthermore, friends and family members who have good eyes also explain to a blind person what things look like that they can't touch, such as a cloud. They would say something like "a cloud looks a bit like when you have a blanket and you scrunch it up... but they're also slightly transparent..." etc. Such descriptions might not give the blind person a 100% accurate idea of an object but in general, they still help a lot to get an idea of what something looks like. As for colors: unfortunately I don't have this skill but there are even blind people who can tell what color something has simply by touching it. They don't know what blue or red actually look like but they are able to tell the difference between a blue and a2