Some consider it cheating, they’re wrong for most practical intents and purposes. There are obvious drawbacks and challenges to working from photographs, but as long as you are interpreting rather than merely copying photographs are just another tool/resource in your bag of magic tricks.
I use photographs a lot with my paintings. You cannot capture every event yourself. Also, the painting is a artistic interpretation of an image, each person may paint something entirely different. You can also incorporate other images into one painting, therefore you are creating something unique.