A couple of my villagers have been around for a couple of years, so I've gotten Tom's pic about 10 times.
Most of my folks, both current and former, have given me pix outside of April Fool's. Off the top of my head, not counting move-outs and April Foolishness, I've received them (sometimes multiple times) from: Cherry, Ruby, Anabelle, O'Hare, Shep, Bluebear, Baabara, Ren?e, Beau, Biskit, Camofrog, and the aforementioned Tom.
In Saalatu I've gotten Papi's and Drake's pics (wasn't as focussed on friendifying the villagers and didn't play for a long time). In Earl I've gotten Gigi's and Anabelle's, but with the exception of a couple of the villagers, many are recent move-ins.