I then purchased a package of clear Christmas ornament balls.  I measured the size of the balls as closely as I could and cut the pictures to approximately that same size. I took the cap off of each of the balls and rolled the pictures so that they would fit into the hole at the top of the ornament and inserted a picture in each one. 

The pictures unfolded themselves once inside the ornaments.  I replaced the tops and put the ornaments back into the box.  I wrote a letter about our many great memories of Christmas and how that I hoped these would bring back those memories each year as she placed them on the tree.  It made for a nice surprise and one of those gifts that "keeps on giving."