Personal and professional photographs are frequently staged, cropped or altered:

• For dramatic or aesthetic impact
• To correct imperfections (e.g., red eye, exposure setting, color correction)
• To deceive the viewer

You can compare shadows on similar objects to see if the light source is consistent. Another method is to draw lines to check the light source.

• Draw a line that connects a point on a shadow with its corresponding point on the object.
• Repeat for all the shadows in a photo.
• If the shadows are real, the lines will either intersect or be parallel, indicating the location of the light source.

Tip: Slight errors in matching points to shadows might throw the lines off slightly, but large discrepancies indicate editing.