Columbo probably put it on his expense report, especially after solving the case.

And he also took the time to count how many pictures were in the book!! Now there is dedication!

wonder if mrs. columbo helped

I wonder if he recognized any old arrests of his while counting all those photos?!

That would have been a good joke... Columbo flips through the book looking at pictures of cons, and they're all photos of Robert Culp, Jack Cassidy, etc.