The ray diagram exhibits spherical aberration. Where the focal ray goes and where the image is don't quite match. The further you get from the principal axis the worse this problem is - it's best to draw objects reasonably small compared to the size of the mirror.
The table shows what happens to the image as an object is brought from infinity toward a concave mirror.
| Object Position | Image Position | Image Characteristics |
|---|---|---|
| At infinity | At focal point | Image is a point |
| Moving from infinity toward C | Moving from F toward C | Increasing in size, real, inverted, smaller than object |
| At C | At C | Real, inverted, same size as object |
| Moving from C toward F | Moving from C toward infinity | Real, inverted, larger than the object |
| At F | At infinity | Infinitely big |
| Moving from F toward mirror | Moving from -infinity toward mirror | Decreasing in size, virtual, upright, larger than the object |
As long as the image as real the ray diagram is reversible. An object at point A creates an image at point B, while an object at point B creates an image at point A.