I don't see any evidence of mites in that picture.
However a good thing to do would be to put some white papertowls or plain white paper in the bottom of your eclosure and let your snake crawl around on that for a little bit. If you see little black bugs all over the paper/papertowls then you have a mite problem.
To check on the snake, they are usually most visible around the eyes and nose. Mites are about the side of the head of a pin, so they are small and you have to look closely.