No reason you can't use a photo sourced texture if your going for a realistic style.
a lot of people use them with great success, I understand you just put those on there and haven't worked on them yet.
But yeah, grab and slap not good! You MUST give photo sourced textures much Much love and attention before using them.
If you can do realistic style from scratch that will wow everybody for sure, but you better learn how to paint really fast, cuz the wow factor won't last and they'll be waiting on your next texture! Also not good... ;)
Other than that it all looks pretty good, just the wires on the one section with the single window that sits on top of the section with the big blue door. The wires are a bit messy on that and could affect your lighting etc.. keep em coming, don't stop now!