Hi, Jeremy! My impression is that he didn't do a lot in the way of public appearances in the last four years of his life, which is why there are a lot fewer pictures of him from that time. A lot of the ones we do have are related to him being arrested and tried over the altercation with the dog trainer, in 1970, plus a couple of formal portrait photos (possibly airbrushed?) from the winter of 70-71, plus a surprising and eerie number from April-May 1971: some of it is because he was doing some relatively high-profile stuff in Nashville in that timeframe, but others are just kind of random.
Dave Phillips has one that used to be on his facebook account, a small polaroid believed to have been taken on May 27-28, 1971, in Atlanta, before he set out on his last plane trip. That would be the "last ever" picture of Audie Murphy. It's a head-to-thigh length shot of him posing with a woman of his own age or a bit younger-obviously a fan. He's carrying a pair of sunglasses in one hand while wearing a medium gray blazer and pants and coordinated tie with a charcoal-colored shirt. You can't make out his face very clearly because it's a smallish pic: the net impression I got was of a friendly, but jet-lagged expression with only a mild smile-no teeth showing. He looked very flushed or suntanned for some reason, at least compared to the woman in the picture.
Here's a couple from Vic Mizzone's collection on flickr:
Murphy with radio personality George Putnam, ca 1968: http://www.flickr.com/photos/41976766@N00/4337801909/
Murphy with Scott Turner's wife and the Turners' infant daughter (Murphy's goddaughter?) ca 1968-1969: http://www.flickr.com/photos/41976766@N00/4201885088/
Murphy ca 1970, chatting up a boxer with his lawyer, the boxer's manager: http://www.flickr.com/photos/41976766@N ... hotostream
screencap from 1968 tv interview, probably talking about veterans' issues:http://www.flickr.com/photos/41976766@N ... hotostream
formal portrait, winter of 1970-1971:http://www.flickr.com/photos/41976766@N ... hotostream