Solution 1:

In the industry they're called "art books", but everyone actually calls them "coffee-table books".

(Because people leave them on their coffee tables -- the long, low table in front of the couch -- to make guests think they're cultured.)

Solution 2:

In book publishing, a book of this size is called a folio.

Books taller than 13 inches are called folios, and are often too big to sit upright, and have to lie on their sides on a top or bottom shelf, or on a table somewhere. These include what are often called "coffee table books"