The multi-color graininess (look at the parking lot) is digital noise.
The big dots are... maybe a dirty lens?
If the dots are light rather than dark, then they are particlulate (water droplets, snow, dust, etc) in the air illuminated by the flash. Water droplets are especially good at reflecting the flash back to the camera. If they are dark and very unfocused, they can be something located on the lens.