Clem Hall did A version of the portraits back in 1982, but the more realistic portraits were already in place at the 1971 opening of the WDW mansion and I'm sure they were also placed in the 70s at DL. The Clem Hall versions are just one of many. Interestingly, in Jason Surrell's book about the Haunted Mansion, there is a photograph of an imagineer painting the portraits in triplicate and the caption is that they were being prepared for the Tokyo mansion, which opened sometime in the early 80's as well. So, if this is accurate, the printed portraits didnt come until much later and they were still being hand-painted all throughout the 70's and early 80's.