Jewelry and accessories are generally allowed when you get a passport photo, but they shouldn’t obscure the face or create any shadows that could interfere with identification. For example, small stud earrings and necklaces are allowed, while larger earrings may cause an issue. On US visa photos, you can even keep your piercings if they don’t change your facial features.
If you’re not always wearing your jewelry or piercings, perhaps you’ll be better off taking them for the photo as well.