Link to the photo must be a reliable URL in the Internet because the photo will represent you to other people.
If you already have uploaded photo to social networks, you can copy its link address and paste here.
Otherwise, to place an image file you can use http://imgur.com/ or other image hosting service.
Go to image hosting, upload your photo, copy image's link address , paste here.
Link to a photo is suitable if you see the photo next to the registration form below.
Make backup copy of your data. It can be useful in case of restoring access to your account.