Is there a simple way to determine or prove this? Real images are always inverted, and unlike virtual images can be projected onto a screen (I'm not even sure what this means to be honest). If I look at the back end of a spoon (convex mirror), the image is always upright and therefore virtual, in back of the mirror. Makes sense, since I'm in front of the mirror. Then I turn to the concave side of the spoon and keep it less than one focal length away from me, still the image is virtual and upright, and supposedly still in back of the mirror. But after moving the mirror more than a focal length away from me the image is now inverted, and therefore real. Does this mean it's in front of the mirror? I can't tell the difference. Please clarify and correct any misstatements/misassumptions.