I took some pictures last night with a D50 w/ 50mm f/1.8, and I noticed some weird faint ghosty images of the neon light letters in the image. What's kinda interesting is that these ghosty images're inverted on both the X and Y axis.

If you look closely above the N in Bennigan's, you can see the image, and follow it to see the entire word flipped on both axis.

Any idea how it got there. Perhaps the image came out of the viewfinder, in to my glasses and then reflexed back in through the viewfinder?