What a Good Source Photograph Looks Like
Light. Natural light is the painter's preferred light, and it has been since the seventeenth century. A photograph taken near a window, with daylight falling on the dog from one side, gives a clear three-dimensional read of the face. What you want to avoid: on-camera flash. Flash flattens the face into a two-dimensional plane and frequently produces a hot reflective spot on the muzzle.
Eye level. Get down to the dog's eye level. The instinct is to photograph the dog from human eye level looking down — but the portrait will be displayed at human eye level on a wall. The source photograph should match.
Sharpness on the eyes. If only one part of the photograph is in focus, it should be the eyes. Eyes carry the dog's specific identity in a way nothing else in the face does.
A relaxed expression. The best dog portraits do not come from posed sit-stays. A better source is the photograph where the dog is relaxed — looking just past the camera, or watching something happen in the room.
Head and shoulders, not just the face. Send a photograph that includes the full head and at least the chest and shoulders. Head-and-shoulders is the single most useful crop.