A great idea for a brag book is to use a 5 X 7 album (like Creative Memories' Sentiments album) and adhering  3 X 5 or 4 X 6 photo sleeves to each page.  By decorating on or around the sleeves with general themes, you allow the recipient to have a unique and creative gift while still being able to change the pictures in the album on a regular basis as the kids grow.