A hidden photo pocket is a fun scrapbook element or feature for a mini album when you want to create an interactive page in your mini scrapbook.
I found this idea on the Craftside blog. I changed it just a bit to give it my take on it.
Cut a piece of double sided cardstock to 6 inches by 6 inches. Draw a 4 inch square in the middle of your cardstock, leaving a 1 inch margin all around.
You are going to cut out most of the square you just drew. You are going to cut 1/2 of the top side and 1/2 of the left side. You will cut all of the bottom side and all of the right hand side.
Fold the bottom left corner up to the top right corner. Use a bone folder to get a nice crease.
Now unfold it and score it in half vertically and in half horizontally. Adhere a photo (or alternatively a scrapbook embellishment of some type) to top right square area. This is my daughter and our family dog. Another idea is this could be a great place for some secret journaling.
Optional is to add a patterned paper to the top of the square and to add a clasp or closure. This kind of hints that there "might" be something under there.
Adhere to your background paper. It is now ready to go into your mini scrapbook!
You could also do this on a full sized scrapbook album and use it either as a small element in part of the page, or super size this whole thing and make it "the page!"