I have taken snakes outside to take pictures, but I warn you that this can be potentially dangerous if you are not careful. Snakes are cold blooded, and if their temperature gets too high or cold they will die. I have talked to breeders at the Daytona show who sold corn snake hatchlings. The new owner went out and put the snakes in their car, inside the parking garage. 2 hours later they came back, mad and complaining that their snake had died. So small snake left in 100+ degree heat won't last long.
I suppose that there could also be a slight risk of mite infestation by putting them in grass or on soil. In my case, I only took them out long enough to get the pictures, and I was careful to put them in the shade, on freshly concrete or cleaned rock surfaces or on plants that seem clean. The air temperature was also ideal (mid 80's). I haven't had any problems with doing this.
Mark