As well as your passport, we need a recent photograph of you. It confirms that the person applying is the person in the passport.
The rules
A plain background, white or very light, with nothing behind you
Your whole face in the frame, centred, looking straight at the camera
Eyes open, mouth closed, neutral expression
Even lighting, with no strong shadow across your face
No sunglasses, no hat, no hood
No hair falling across your eyes
No filter, no beauty mode, no retouching
It must be different from your passport photo
A photograph of the picture printed in your passport is not accepted. Neither is a screenshot of it. It has to be a new photograph of you, taken recently.
Taking a good one in thirty seconds
Stand facing a plain light wall, about an arm's length away from it.
Face a window rather than a lamp, so the light is on your face and not behind you.
Ask someone to take it, or use a timer. A held-out arm distorts the face.
Take off glasses, hats and anything covering your hairline.
Check the result: is your whole face visible, is anything behind you, is it sharp?
Children and babies
The same rules apply, with the obvious allowances. For a baby, a photo taken lying on a plain white sheet usually works. Nobody else may appear in the frame, including a parent's hands where they can be avoided.
What happens if it does not comply
We ask you for another one before submitting, and your file waits until it arrives. A non-compliant photo is the second most common reason an application is delayed, after a missing passport image.