According to the U.S. Department of State - Bureau of Consular Affairs, bad photos are the #1 reason passport applications get held up during the application process. In 2015, the US department of state received more than 200,000 unacceptable passport photos! Submitting a passport application with a bad photo will delay processing your application and could interfere with planned travel.
Glare on glasses - It’s tough not to have glare on your glasses. It's actually more common that you think. Glare can appear even when the camera doesn't flash. So, it may be easier to take them off. Starting November 1, eye glasses will no longer be allowed in passport photos.