And just throwing something in here to The Thread 2
Over the years the stretch portraits have evolved from the Marc Davis sketches into more realistic paintings seen today. As you can see from the originals in the Osmond Special, the earliest renditions (concepts of Davis, though not actually painted by him) were the first. Over the years they were modified. From what I have been told, the cut down (cropped) versions from Disneyland are currently in the Chicken Exit of the WDW Mansion. While I have seen them in person, I can't honestly vouch for wether they are originals or just prints.
Seen in this image is the Marc Davis originals, the ones from his concept and lastly the current version today.