Painting from photographs can get you into trouble. Why? Because trying to copy a photographic reference exactly is a sure recipe for disaster. Here are some reasons:
In other paintings, say a landscape, I often search for photos of certain types of trees or bushes or even flowers to use as references. How can you paint something realistically without knowing what it looks like and how it's put together?
Pleine aire painters will grumble at my theory; but they have the luxury of being there, on the scene, to capture the atmosphere and light as it happens. And more power to them. I'll stay in the studio.