I think (if nothing has changed) that you can provide up to 20 photos of your relationship. You need to proof your marriage is genuine and the wedding is part of your marriage (to make it official). So yes, most people would include pictures of wedding ceremony. And it's usually where friends and family come into picture. So more to show that the relationship is known to the public/family.
In my case, I used a few photos from our court wedding ceremony, as our actual wedding hasn't taken place yet. I also included other photos, such as moments with my husband's parents and friends, our travels, his proposal, and times spent with my friends and family. Beneath each photo, I added a brief description and the date it was taken.