(and my other favourite, the dreaded STAPLE question).
haha, I used three paperclips to hold my two (headshot) photos to a blank piece of paper. Please don't yell at me.
n.b. I submitted 20 photos and had three of the wedding, two separate photos with each a different friend of ours in them, one of the two of us in a crowd, and 14 of just the two of us in various locations where we've travelled together in Canada, Netherlands, Germany, and Bermuda taken at various times of the relationship.
All the photos were digital so I used MS Word to put each picture on a page that included my name, d.o.b. and UCI (Many people won't know this number but I have one from previous work permits). Underneath each photo I put a brief description (max. 2 sentences). So perhaps I didn't follow the instructions to the letter either (writing on the back of the photo), but the spirit of that requirement has to do with printed photos from a photographer, and should not slow the application down.
Submitting too much information, however, does have significant potential, if many people do it, to slow things down for everyone who applies and not just the offender. So please... please, just send the requisite number of photos and other supporting documents.