I have several set of images with a fixed background and an object moving in the foreground. I'd like to get an idea of the motion of the object by superimposing images with scaled opacity. If I load a single bunch of `N` images into GIMP as `N` distinct layers, is there a way to *automatically* set the opacity of all the layers to get a scale effect from the first with `P1%` (e.g. 0% opacity) to the last with `P2%` (e.g. 100% opacity)? Thanks in advance