People use this site for different purposes. Just because I own a card, doesn't mean I've had the opportunity to "add it to my collection" on here. Me, personally, I use the site right now to track complete sets or those that I'm attempting to complete. My want list has more than that, and I've actually gone in after trades (where transaction manager was correctly used by both parties) where the cards weren't part of sets, and deleted them from my "collection". I've also scanned cards before packing them up and shipping them to another collector (sale or trade). A lot of the newer inserts/parallels get scanned for here first, then I put them up on ebay.
So, in short, just because someone added a scan to the site, don't be alarmed if it's not in their collection.
As for reprints being used for the originals - personally, I'm not a fan. I'd rather see a beat up, creased card shown here than a clean reprint. Maybe Admin would rather see clean-looking cards. I don't know. I can't speak for Admin! :)
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 3/4/2024). I have added a large portion of my inventory to the site, and currently have trading turned on (details are in my profile).