Just look at reflections and if they're making sense. Or, when it's a face, then look at the reflections in the eyes. Left/right eye should be consistent (reflection should look the same).
When there's nothing reflected, then inspect the shadows thrown by objects.
But, when there's a bad image quality or things like winter landscapes and people walking without exposing too much of details (ie picture from behind) - good luck.
When there's nothing reflected, then inspect the shadows thrown by objects.
But, when there's a bad image quality or things like winter landscapes and people walking without exposing too much of details (ie picture from behind) - good luck.