Including Identification Details

I really like this picture of my great-grandparents and their two youngest children. Unlike many photographs I have, it doesn't seem staged--the clothes are on the line, after all. And the daughter seems to be shooting her father a funny type of look. 

But identifying the picture got me to thinking...

I'm still toying with ways to include "metadata" with pictures. I realize that when creating graphics files there are other ways to include details such as those I've written in black on this document without putting them on the actual image itself.  One concern I see is that not all users of graphic images readily access such metadata and some may inadvertently bypass it entirely.

Genealogists who are not necessarily adept with their computer skills may simply copy and paste the image into their own graphics program or genealogical software--thus bypassing any "metadata" that is not an "immediate" part of the image and unintentionally overlooking key information.

Who is in the picture is important, but I'm starting to become convinced that some of the "chain of provenance" and "how" we know who is in the picture or where it is taken is important too--just as important. There are many pictures on the internet that are identified, but if one simply "copied and pasted it," how does one know if the identification was correct?

And if the image gets saved without any identifying information, then it's just an old picture of some dead people.