The only pictures that go into them are the ones the person has learned very well. I have seen communication books that have as few as three pictures in them to others that have several hundred pictures in them. Picture types range from family or detailed photos to basic black and white line drawings. The type of picture chosen depends a lot upon what the person can comprehend. For them maybe the basic black and white line drawings may work just fine.
Therapists often try to accommodate the needs of the whole family.
We teach and include pictures of basic wants and needs first, such as eat, drink, bathroom, hygiene, etc. As they begin to learn these pictures more can be added. They have become popular with others who need to communicate with the non-verbal as well as only family and friends. Even fast food chains have made picture books for the hearing impaired and other non-verbal customers to order from. Sometimes families decide it is too much of a hassle to carry it around with them.