A common symptom of eye cancer is a white pupil in one or both eyes. This is called leucocoria and in children can be because of an eye tumor called retinoblastoma. However, other color changes are not so significant in terms of cancer. Since you have seen this in a photo, i suggest you see his eye yourself in normal white light and see if you can make out any difference. If not then be rest assured, its nothing but a camera thing. If you do see a difference, there is no harm seeing an eye specialist. It may be something other than cancer.