illustrated reference book; pictorial book; field guide
A book that uses many pictures or photographs to identify and explain things, such as animals, plants, or vehicles. Often used for children's encyclopedias and nature guides.
The child is looking intently at an insect picture book.
I looked up the name of this flower in an illustrated reference book.
I looked up the insect's name in a field guide.
This butterfly is pictured in the field guide.