today I learned that imagemagick can read gimp's project files, and treat each layer as a seprate image. This. Is. Huge. It means that now finally we can have something that is close to "Save all images".
for example magick template.xcf layer_%d.png would save each layer as layer_1.png, layer_2.png, etc
and here's a preview in my image viewer:
I discovered this by accident, as I was trying to montage images into a single image, I kept seeing some source images being included that weren't really exported in the image directory. Turns out it was the xcf file :)