Top: The formation of a real image using a convex lens. Bottom: The formation of a real image using a concave mirror. In both diagrams, f is the focal point, O is the object, and I is the image. Source Wikipedia
A real image occurs where rays converge, whereas a virtual image occurs where rays only appear to diverge. Source Wikipedia
In ray diagrams ... real rays of light are always represented by full, solid lines; perceived or extrapolated rays of light are represented by dashed lines. Source Wikipedia
Because the rays never really converge, a virtual image cannot be projected onto a screen. In contrast, a real image can be projected on the screen as it is formed by rays that converge on a real location. Source Wikipedia
In diagrams of optical systems, virtual rays are conventionally represented by dotted lines. Source Wikipedia
a virtual image is found by tracing real rays that emerge from an optical device (lens, mirror, or some combination) backward to perceived or apparent origins of ray divergences. Source Wikipedia
A real image is the collection of focus points actually made by converging rays, while a virtual image is the collection of focus points made by extensions of diverging rays. Source Wikipedia
