I'm not sure if I understand all the details of your situation and the pix that you linked to, so before I make any attempt to seriously answer your question, I'm going to try to state each point I think you are trying to get across, the nature of each photo, etc.. Please respond to each of my questions. I apologize in advance if this approach comes across as didactic, but there is lots of room for mis-interpretation here and I want to be sure I get everything right.
1. You didn't take any of the photos that you linked to. Yes or no?
2. Some of the photos you linked to were supposed to be shots of the camera you bought, but you think they have been doctored. Yes or no? If so, exactly which of these are you concerned about (by file name, please, not "the first one", etc. -- the ordering of pix changes depending on the browser we are using to view your post, etc.).
3. Now that you have possesssion of one of these cameras, you see what appears to be a silvery coating on the sensor. ... Yes or no? In other words, you are not trying to infer a silvery coating from these pix are you, yes or no?
4. You have not supplied us with a picture of the sensor that you took yourself. Yes or no? If no, why not?
5. You are worried that the seller has used Photoshop on the pix he took to hide the silvery coating that you see. Yes or no?
6. You see the silvery coating over a large portion of the sensor? Yes or no?
7. ... but for some reason, you are concentrating on a perceived anomaly in a small area in the (viewer's) lower left hand corner of the sensor? Why? Do you see this anomaly by eye when you inspect the camera now in your possession?
8. Can you please either (a) supply the URLs of the web pages which had all the variants of the main photo, eg, noise, luminance gradient, etc; or, (b) if you generated these variants yourself, why did you do this?
Now, a couple of general comments:
A) I hope you realize, of course, that probably every single one of the photos that you posted has been through some image editing program, if for no other reason than to remove the background, so looking for any hidden metadata (to try to determine the processing history) isn't going to tell us anything.
B) I hope you realize that depending on the exact lighting used to illuminate the light box of a dslr, the sensor can take easily take on a silvery look, show rainbow-like diffraction patterns, look almost black, etc. In fact, a lot of uninformed sellers don't even know enough to lock the mirror up, so that when they take a photo, it actually is showing the focusing screen or the mirror (on dslr's), not the sensor.
C) If none of the photos that you linked to was taken by you, and is of the camera in your possession, please try to take some photos yourself, even if the only way to do this is using your cell phone. Experiment with and post pix taken under different lighting conditions.
Cheers,
Tom M
