Hi, It looks like that older sepia-tint photo had been in the book and slid out. And I remember in that crime scene photo it looked like other squarish/rectangular items also lay nearby the book on the ground.
It only makes sense to me that whoever dumped Caylee there
put at least the sepia photo in that book before putting the book in the bag. Maybe those other items had been in that book too!
I'm thinking maybe they discovered a photo snapshot like the ones on the coulage board we have a photo of. That family took a lot of photos. Something that this person wanted to dispose of or even something like a photo of Caylee's real dad.
The investigators would want to locate the other photos from that roll of film, right, to tie it to the house. Especially as if someone like Casey {airhead} tucked photos in a book she probably wouldn't think to wear gloves. But of all the prints on that supposed photo, the last one to handle it would be on top.
So evidence like this could tie the remains scene to the house and also directly to whoever prepared the bag for disposal. That would logicaly be the killer IMO.
If not a photo it could be a letter, receipt, etc.
Any ideas?