Typically two to three images are needed to properly diagnose and treat a skin condition.
Use your device to take one photograph from a moderate distance of 2 to 5 feet. It should show the location and distribution of the condition.
Take 1-2 photographs from close up, usually 2-4 inches. These need to be sharply focused to show the detail of the particular skin problem area.
The images below are good examples of proper image resolution and detail of a skin condition. Image sizes should be between 0.5 megapixels to 4.0 megapixels.