[ALUG] Convert a photo (.JPG) to an icon - how?

This is probably a trivial question, but still.... How can I convert a photograph (probably stored as a JPEG file) to an icon file that I can use as my favicon? It would be useful if, on the way, some sort of tone separation process was available to make it work better as an icon too. -- Chris Green (chris@areti.co.uk) "Never ascribe to malice that which can be explained by incompetence."