Hi Matthew,

how many photos from WLM 2012 have already been incorporated in Wikipedia articles (total and by country)?

Same number than Arild using he tool pointed by Andrea:
(In main namespace only:

Distinct files used = 48,998 (13.3% of all files),	Pages using files = 15,377 ;	Total file usage = 59,917

)

Also, how many monuments that didn't have photos before have photos now (total and by country)?

See <https://commons.wikimedia.org/wiki/Commons:Monuments_database/Statistics>

and make the diff with the revision before September 1st (though obivously monuments lists will have been improved during that time)