How do you average two images ?
Manually, you leave bottom image at 100 opacity.
Set top image to 50 opacity.
But i used a script to do this that uses other scripts.
https://gimplearn.net/viewtopic.php?p=1812#p1812
Then I usually bump up the contrast after getting the average, because most of the time the average looks low contrast.
makes an interesting horizontal banner because it is seamless (horizontally).
Would work great for a blog header. Must try this. Thanks for the idea