Supplying a photograph

A good quality photograph (clear and sharp) that captures the character of the subject is essential for a perfect result.
Photographs taken from mobile phones are generally not good enough unless a minimum of 4 to 5 mega-pixel camera is used. The higher the better of course and
most modern digital cameras provide an even better definition which is ideal.

I would strongly recommend providing (if possible) more than one photograph as it gives a better understanding of the personality of the subject as well as the colour scheme.
If you are not sure which one to choose I would be happy to advise you (sometimes a not so obvious lighting of the subject or a contre-jour can provide a great opportunity to enhance the quality of a picture at its best).

Avoid using flash photography
Casuals, off guard photos often make more interesting portraits than posed shots.
The chosen subject can also be selected from a bigger scene (group etc) as long as when isolated it keeps its high quality definition.
Backgrounds are of no importance.