Towards the lower right hand corner there is a green dot. I left the image kind of big so it is noticable. This happened in two out of about 200 pictures I took last night while doing some sunset photo taking.
#1. "RE: D50: Digital Green Dot on photo" In response to Reply # 0
I'm no expert but it looks very much like ghosting, caused by the bright light of the sun reflecting inside the lens. If you have a protective filter on the front of the lens, it may well be better, if not gone, when that's removed. My protective filter is already horrible and smeary, and in challenging lighting it doesn't seem to introduce flare, but makes existing flare pretty nasty.
#4. "RE: D50: Digital Green Dot on photo" In response to Reply # 0
That's one of the classic side-effects of light bouncing off the sensor, against some lens element (usually a "protective" UV filter, lenses themselves are pretty well designed to not do this). The tell-tale sign is your green ghost appearing 180º around center from a bright light source.