The U.S. Department of State requires that passport photos be taken within the last six months of the renewal application submission. The photo must reflect a person's current appearance. It must be a color photo with a full-face view, taken without glasses or any other item that covers the face.
The photo must measure 2 inches by 2 inches, with the face measuring 1 and 1 3/8 inches from the tip of the head to the bottom of the chin. It must be printed on photo-quality glossy or matte paper. As of 2015, the passport office allows digital photos, as long as they meet pixel and size requirements. Going to a professional passport photographer can help avoid having to retake and resubmit photos.