A few days before the Aloha show in Hawaii - January 1973
The current owner of the photo, Richard Foster, has been posting in the Elvis Pictures Facebook group, where the photo can be found. He confirms that the photo is from 1973, as the woman who took it was in Hawaii specifically to see the Aloha show. Here's what he says:
"It is from 1973 - the lady I got it from said her friend was in Hawaii to see the Aloha show. She saw Elvis at the hotel, and the picture was taken...that's about it. It had been sitting in an envelope for 50 years and the lady actually forgot she had it. The lady who took the picture is no longer with us. And I was born a month later so I was not there. That's all I know."
Thanks to DarrylMac at FECC for the extra details