Here is a little video tutorial demonstrating one way that I am making postcards. You can use this method to make Teeny Tiny Art of any sort, postable or not. I'll demonstrate this and other methods in a FREE POSTCARD WORKSHOP at Art and Soul in Kansas City on April 4.
Here is the 8"x12" piece that I created in the video:
And the four cards that resulted:
Download the Step-By-Step here.