Dogs have a reflective layer in their eyes known as the tapetum lucidum. This layer is reflective, and helps with night vision by reflecting light back into the retina, and thereby increasing the available light. Normally, if you take a photo of a dog eye straight on while using a flash, the pupil will appear yellowish or greenish due to the reflection from the tapetum lucidum, although it may also appear other colors in the photo as well due to various conditions. However, if the dog's eye consistently appears red in photos, it is possible it lacks the tapetum lucidum in that eye.
As discussed on the Dogington Post, lacking a tapetum lucidum isn't necessarily concerning. The dog will presumably otherwise have a normal life, with poorer vision in low light conditions than other dogs. It may also be possible the dog only lacks the tapetum lucidum in the one eye, or by natural variation the eyes aren't entirely symmetrical in the face, resulting in only the one eye showing eye shine at a time.
What you should be on the lookout for is if the eye shine in the eyes, in the case they are both shining the approximate same color, are still consistently distinctly different, which could be an indication of a problem with the retina of one of eyes, or if the different eye shine is being caused by differently sized pupils, which is also a possible sign of medical problems.
In conclusion, it most likely isn't something you need to schedule a vet appointment for, but it would be good to ask about it in your next visit.
I have a two months old puppy and she's adorable. I've never had a puppy before and I'm learning as I go, but I'm constantly terrified that she's going to get sick or hurt or something. 
