What algorithm is used to fill transparent areas like this?

Question

Algorithms

Can anyone suggest the name/description of the algorithm used to fill transparent areas of an image in this way?
Maybe there are some utilities that can batch process files with such a result?

Answer 1

If simplified, then something like this:
1. Extract dominant colors from the original image , selected from the palette of unique images.
2. We generate a background image by setting the previously found dominant colors.
3. Overlay the original image on the background.