The official capacity is still 16,000. They did renovations, lowering the playing surface, which were supposed to allow them to expand to 20,000. They never did any of that though.
It's not a matter of taking a picture and looking at the number of people in the seats for attendance. I went to three games last year (attendance), Missouri State (26,482), Weber State (25,888) and NAU (26,229). All of those are above WA-Griz capacity (25,217) and there was plenty of room to stretch out and be comfortable around me for all three. Attendance is based on ticket sales.
Not saying Idaho didn't fudge the figures some, I think they played as the home team in Pullman one year against Washington State and they gave away a bunch of student tickets. Back when we called Dornblaser home turf, there were plenty of people in our camp that would have played there, and when it was built in 1972 or whatever, they were going to have an open air stadium because they were trying to move up. When the deal fell through on that, someone made the bad decision to put a roof over it to make it look like that quasit hut in Pocatello.
Thank the heavens that when we moved, the new home was made for expansion, and for a roof that I hope anyone ever allows.