In the past, here's how it worked:
You submitted a photo, and it was sent to all programs automatically once available.
The photo was "screened" (i.e. I couldn't see it) until you were selected for interview.
Problem is, nothing stopped me from clicking the "Select for interview" box, looking at your photo, and then unchecking the box.
So now:
You submit a photo.
You can release the photo to individual programs, any time you want. This allows you to do so up front, or wait until interview decision are made.
Once you send it, I get to see it right away.
Does not sending a photo hurt you? I would hope not. There are two possible scenarios:
1. Program offers you an interview, then sees your photo and decides that they no longer "like" you. Needless to say, they'll come to the same decision when you actually interview whether you send a photo or not.
2. Program doesn't offer you an interview because of a missing photo, because either a) they worry you have something to hide, or b) because they consider the photo a part of your application and hence your application is considered incomplete and not reviewed.
#1 seems a non issue -- would you really want to go to a program that would not interview you based on your photo anyway?
#2 seems very unlikely and highly paranoid. I guess if you're applying to a very competitive field and they're looking for reasons to reject applications, it's possible.
So, personally I expect it doesn't matter.
I would upload a photo once you have an interview. This way, we recognize you when you arrive.