Sometimes the picture may show distracting dirt-like marks. They are called sensor dust/stains and are caused by frequently changing the object lens and also by the sensitivity of the camera sensors.

 

The disadvantage is of course that one can recognize them in the picture, even if minimally. Therefore, we recommend to check all of your pictures with 100% magnification and manually remove the sensor stains with the repair or stamp tool in Photoshop if necessary. Make sure that you always keep your camera sensor clean, since dirt stains on your pictures decrease the chance of sales.