What are the possible causes of white spots on photos and how can they be prevented or removed?

White spots on photos can be caused by dust or dirt on the camera lens, sensor, or film. They can also be caused by condensation or water droplets on the lens. To prevent white spots, regularly clean the camera lens and sensor with a soft cloth and avoid exposing the camera to moisture. To remove white spots from photos, use editing software to clone or heal the spots, or retake the photo with a clean lens.