I take as many pics as I can when I am on the job site. Of course, I get gried from the contractors a lot because they think I am spying on them or something. When they give me grief for taking their picture, I just ask if it is a Religious objection to having their photo taken. Of course, when they say NO, I tell them to mind their own business and get back to work. If they are doin it right, they got nothin to worry bout. Plain and simple. I have a hangar I designed underway right now, it is about 80% complete and I have almost 700 MB worth of photos taken at med-to-high resolution digital cameras, totals over 2000 now I think. I have used the pics in several cases so far to force the contractor to remove and redo, or repair, several items. Also great record for the owner.
If you are worried about it, make sure the owner/client gives you the OK to take pics. Once you have that, I basically ignore any concerns that any of the contractors have about me taking pics of their work. They are paid to do a job right, and we as the engineers are paid to make sure it gets done right.
However, I also do a lot of work on military facilities, and particularly in some classified areas of the facilities. THis gets very tricky for picture taking. I like to try to get it in my contract in advance for permission to take pictures on site, even if they have to go thru a screening. If not, make sure that the military (or other high security organisation) will grant you access to one of their personal with photography rights if you want to get pics of work being completed.
I also concurn with RDK above. If your company doesnt want pictures, seriously consider their motives. I wouldn't want to be arround that mentality.