There are 3 pictures that you would need to upload.
Picture 1: A valid government issued ID with 3 specimen signatures
Place your ID on a piece of paper and sign 3 times underneath the ID. Kindly sign consistently and the signature should match the signatue on the ID.
Sample:
Picture 2: The back portion of your ID
Take a picture of the back portion of your ID
Sample: 
Picture 3: A selfie
Take a picture of yourself with no hat or sunglasses.
Note: Each file should not exceed 4MB in file size.