SimpleCV. The cropped image is from a frame which does not have foundation. Presumably, this light colored wax was used to store honey.
If you see the hexagonal boundaries, then you know that the image is rotated - the bottom of the frame is found to your left. In the book The Buzz about Bees, Jürgen Tautz describes how bees convert tube-like wax cells which resemble the shape of the bee body into a hexagonal wax form. In the image, circular-ish tube-like cells are surrounded by hexagonals.
I colored coded the SimpleCV identified circular-ish cells - green are larger and blue are smaller. Part of the image is over exposed, so a few cells are not detected. As you can see, like sized cells are found next to one another. Also, cell size varies with the most likely between 5.1 and 5.2 mm.