These two photos were taken just a few seconds apart:

http://homepage.mac.com/christopherjcampbell/Problem%20Photos/

The first was at f/6 and 1/6 second; the second at f/22 at 5 seconds.
Both photos were taken with a tripod and no adjustment has been made
for color balance, sharpening, or anything else. They are just JPGs
taken straight from the raw files. The lens is the 12-24mm AF-S Nikkor.
The scene is a night photo of Heritage Street in Vigan City in the
Philippines.

I can understand how stopping down might cause the star filter effect
seen in the second photo, but where did the strange dots come from?