Another hoax...
John & Cindy McCain were celebrating his 25th anniversary of retirement from the Navy on that same evening.
How do you know that? That they celebrated together? April 1, April Fool's Day heh, missed that.
Another possibility it is a hoax. The photo could have been taken shortly before press time and posed by stand-ins. All you'd have to do is reset the camera date/time. I don't think you can cheat the exif with any of the other data but could be wrong. Then the Enquirer is in on it another way about the date or can read the exif like I did, and presto, a phony scoop.
I thought the article said there were more photos, but I'm not buying that rag, used to now and then for entertainment purposes :-)
I did find a blog that said McCain retired from the Navy in 1981. Now putting in different parameters, several blogs including wiki say John McCain retired from the Navy April 1, 1981. I calculated it to 25 years exactly.