I couldn't seem to chase my husband down for his picture. I kept getting to the point where I had uploaded his passport and then he was always either shirtless (it's been hot around here lately) or running around like a mad man. This is something like how I did it if I recall: Open app, Click on little person icon top right, click on correct guest, check in or edit check-in, scrolled next past the passport part and the next step was the picture.