re: From one of the links you provided...
That's a good report. Still it describes what is most likely, but not everything:
>"Floating dust particles may cause white spots appearing at different positions on pictures taken by a digital camera using the flash. Dust in front of a subject reflects the flash light and the image of the dust is captured out of focus.
Dust, snow, rain, pollen, condensation, or any small airborne particles may cause the same problem. The particle will appear light and big because it is out of focus; it may assume a shape similar to the aperture of the camera, usually round."