File talk:A diagram representing a convex mirror, which shows its focal point, focal length, center of curvature, and the principal axis.png

This figure is flawed. Firstly, it doesn't show the direction from which the light comes. This is important, because it is this (and only this) which determines whether the mirror is "convex" or "concave". (In general, the non-reflective surface can be transparent. One can have a "rear-surface" curved mirror.)

Secondly, the focal length, as shown, is incorrect. The distance to the focus and center of curvature are measured from the reflective surface, of course!--Srleffler 04:16, 11 July 2006 (UTC)
 * The figure was later revised to fix those flaws.--Srleffler (talk) 05:03, 16 October 2015 (UTC)