I was introduced to the Lena image in 1992. My scientist boss gave the reasons for the image being used as to do with the fine details in the feather bit, the spectrum of colours plus skin tone. He was not aware of the provenance of the image.
We also had the baboon and I still use him to this day.
The one I am missing is the Landsat image of the Bay Area.
In 1992 we did not have the www. Or search engines. So there was no way to learn the back story if you just had the image. So we should not judge those that worked with image processing systems and only had a dozen test images to work with.