PAN photo
Use a light background and a clear frontal face. Protean has published more than one size table. This page exports a small portrait aimed at 10–50 KB.
If the PAN page you are on prints a different centimetre size, follow that page.
What usually goes wrong
Do not upload the signature image here.
What this page checks
JPEG starting at 204×284 pixels, 10–50 KB.