Sending reference photographs of people
I find children and adults easier to work from if the images are not too small, 6x7 in. size is fine, as long as the subject is not a small dot on the horizon.
The bigger the photograph the better chance I will have achieving all the fine features and expression of the subject.
Studio portraits or photographs taken outside are perfect. Seperate photos will be fine to work from if you require a group portrait. I can bring them together in the portrait.
I will need reference to colour of eyes and complexion as these are not always obvious in the photographs. Again the better the reference the more pleasing the finished result.