Yah, I agree with fossil and some others. The behanvior of the ants in the picture suggests a differnet species of ant, though not seeing them live, it is tough to say definitively. I've got a new log home and I boarder on paranoia when it comes to carpenter ants. From my understansing, the ants can cause considerable damage,
but it takes a while for that to happen.
Check out
http://www.carpenterants.com/ to be sure. Tons of information there. If you find you do have caprenter ants around your property, I encourage you to watch them closely to see what they are up to. They are probably foraging around your house, and may pop up inside your house, but if you see trailing (evening hours most common) then you could have a nest somewhere in your home. Just my .02 cents, and probably more information than you need, but after researching these things for the better part of the last few months, I've got some information to give away.
Chris