If the head is rectangular, keep well away. It is really difficult to tell from the photo. The colourings almost look like just a common garter snake.
It isn’t a copperhead. They are banded, not stripped. http://comp.uark.edu/~sbeaupre/P3300025.JPG
Here is a good Herp-guide http://herpsofarkansas.com/Snake/HomePage
If I had to guess just on the photo, which gives no idea of how big the thing is or a very good idea of head shape, I’d say garter snake or a brown rat snake.