How big are the photos you’re are “building” with? If they are small enough, you could combine a couple Particle Playground cannons with pictures as particles and then use card dance to fake like those particles are actually landing perfectly on the flat surface (mask the particles so they don’t go beyond the walls).
If that doesn’t work, you could create a large file in Photoshop with a grid of photos and use that as a layer to build your building. Then when you have that where you want it, you can mask off each photo (create several duplicate layers). Create a keyframe for each layer in the position it’s in, then move it down in time and then move it to where you want it to start and add rotation, etc. That way you at least won’t have to position each picture exactly in line with the others- they will already be perfect. It might still be a bit tedious, though. Hope this helps,
Nate