This was taken in a Project Opensky 747 JAL NC at Mount Fuji. 
Here is how I took it: I'm using Windows Vista. You know when the User Account Control window come up, the background become dark, and FSX was right "beneath" it. When the window is closed, I was back on FSX. But at the first half second, FSX went shiny like that (I think it was loading) and I took the shot during the half second (Alt+PrtScr), and I got it.
Here is the link in case you can't see it :
