This is not seen in any episodes.

I purchased this online.

This qualifies as a "fantasy" prop, as it didn't appear in any episodes, but was created with the intention that it was taken from the "Smallville Universe". This is a VERY nicely made, touristy "Greetings from Smallville" postcard. You can imagine that this would be the type of trinket that you could pick up at a drug store in town. The graphic was inspired by the welcome sign displayed in the pilot episode.