A montage (overlay of two different images). One is the oak daily photo from a week ago - http://ed-k-photo.smugmug.com/gallery/6988948_kjHp8/1/468746639_DJbgK/Large - and the 2nd is a macro of peeling white birch bark. I have 100's of texture & background images to use for montages, and this particular birch bark macro is one of my favorites. It gives the appearance of peeling back a piece of parchment to reveal the image beneath.