REQUIRED: High resolution photos, with subject well-lighted. Big and clear. Head should be larger than 2 inches, with good resolution Front-facing subject. We need to see the shape of the face. All of the face.
Clearly show the subject's facial features - eyes, nose and mouth definition. No sunglasses (unless they'll be wearing one in the caricature).
Capture the person's typical smile or common expression. If you want the person drawn smiling, then we will need a photo of the person smiling.
Camera can’t be too close to the subject otherwise the lens distorts the face. For this reason, selfies often don’t work as a reference photo.