Anna: No one guessed that the last mystery photo. Well, here's the solution, anyhow.
It was a pine cone seed. Just the very tip of one. The image was taken with our new zPix digital microscope. It was the first photo we tried taking with it, and it wasn't working well at all. I ended up having to take a screen capture. Philippe then went hunting, found, downloaded and installed the updated drivers, and now it works fine. We might be posting more micro shots here in the future. :-D
Oh, then we got the microscope for free. Those grocery store loayalty points are good for some things! :-D