I just got around to downloading some pictures I took the past few days,\nand also over the summer, from my 4 month old D100. I noticed a small\ndark blotch in the same place on all the photos. Would this be a defect\nin the sensor, or possiboy dirt that got in there? I'm very careful with\nthe camera, keeping the lens cap on and in the case. What can I do about\nit? Thanks.