Comment by yzydserd

Unsurprisingly, macaw test images go way back. There is one in this old Kodak test image dataset that is often used in CG tests.

https://r0k.us/graphics/kodak/kodim23.html

It seems to have been uploaded in 1999 from an old slide dataset.

This seems to be the Photo CD from 1993. I suppose the source goes back earlier.

https://www.math.purdue.edu/~lucier/PHOTO_CD/