Best resource for understanding the nuts and bolts of a house

[Gary Dezoysa]

I remember when I was younger, I had the chance to look at an exercise guide that showed pictures of all the muscles each exercise hit. It really helped me more concretely understand how the muscular system functioned  at a deeper level. I could understand the meaning of targeting the traps versus the lats instead of just "hitting the back."

When it comes to real estate right now, I lack that x-ray vision.

I understand that if an agent tells me a house needs major plumbing system repairs, it's going to be expensive. Same for electrical or HVAC. Conversely I understand that a room with exposed outlets and chipped paint won't cost that much. 

But anything in the middle, I just don't know how to compute, because I have a poor sense of costs of things like wall or floor repair, how to assess hidden damage etc. Here's a room I would be lost on:

http://news.images.itv.com/image/file/373594/image...

What resources could you guys recommend for someone like me, who doesn't have a sense of how to spot hidden damages, and make a rough assessment of repair costs? Ideally a picture heavy reference would be best, although I'm open to anything.

Thanks