Date/Time tags

A scenario: On 2009/10/23 I edited an image that I had originally scanned from a photograph on 2009/09/12. The date stamped on the back of the photograph was 2009/05/16 (the date the film was processed). The picture was taken in a museum on 2009/05/01 during my trip to Washington DC. The subject of the picture is a 2005 painting by Tom Freeman which depicts the bombing of Pearl Harbor on 1941/12/07.

The question: For this image, what should be the values of each of
these tags? (The MWG tag descriptions are in brackets.)

1. ModifyDate - ("modification date of the digital image file")
2. CreateDate - ("creation date of the digital representation")
3. DateTimeOriginal - ("creation date of the intellectual content being shown")

The answer?:

1. DateTimeOriginal - I think it is fairly clear that this should be 2009/10/23, the date that the image was last modified.
2. CreateDate - If we take the MWG description literally this should be 2009/09/12 (the date that the image was scanned), however this date is perhaps not as meaningful as some of the other possibilities.
3. DateTimeOriginal - This one is up for grabs. Any of 2009/05/01, 2005 or 1941/12/07 could be possible.

DateTimeOriginal is the most difficult. What is meant by "intellectual content being shown"? For any other general picture I took during my trip, this would be easy, and it would be 2009/05/01, the date of my trip. However, the subject of the picture is a painting which was created in 2005. But the content of the picture is the 1941/12/07 raid on Pearl Harbor.

I suppose the proper value for DateTimeOriginal depends on the context in which the image is used. If I want to associate the image with other pictures from my trip, then 2009/05/01 is the most appropriate date to use. However, if I am using it to document an essay on American history, then 1941/12/07 is more significant, or if used in a biography of Tom Freeman, 2005 is the appropriate date.

Confusing.