With age comes wisdom. I have had many dogs. A few of them attained a kind of "dog wisdom" that you could see in their eyes. Your dog has it, and you captured it. Well done.
I know it's said to be silly to attribute human emotions and feelings to animals and allegedly Walt Disney has to take some of the blame but this dog's face says she is reminiscing/ thinking /feeling as we do. I defy even non dog lovers not to recognise these characteristics in this dog. Put this picture on the wall and she's with you for a human span of life.
We've had three dogs, all now gone sadly and the wife and I still find ourselves talking about them and situations we remember just as you would if they were human members of the family.