Someone who used to be an immigration officer advised me to keep the application package concise and not put in hundred's of pages. Remember, they are trying to see 1) if your relationship developed according to the norms in your customs (or mix of cultures) 2) there is evidence of relationship
I would suggest no more than 50 pages of photos....you can always indicate on the section "More available on request" and be strategic in what you include (i.e. pictures of you doing things together, pictures showing you with other people in family / friends, pictures that signify relationship (i.e. wedding, engagement, home you share, etc)
Of course in the end it is up to you.
Take care,
C