pictorial signage may be appropriate in some parts of the library but not others.
Photographic elements may help draw people to different sections of the library. The use of space needs to be considered. do they or do they not want space been used. Keep it clear because there is already a lot of visual clutter happening.
The stairs found within the centre of the library needs to be used more as there is nothing in the form of content to distract from pathfinding.
Why not indicate what is kept on the floor the user will shortly be coming across?
clever use of a rounded architectural element.