linking a image with its mask

[rich2005]

I agree with Ofnuts, it is all a bit weird and along the lines of the commercial PS clipping path makers but for Gimp   These are your clips. What you have to what you require.

   

I am no code writer, especially script-fu which to me is a clear as Sanskrit. Thus as a user step-by-step

"manually" using some existing scripts

1. Why the different size layers ? Ofnuts has a good python plugin for layer > image size but sticking with a script-fu sg-scale-to-selection.scm to correct that
2. Duplicate base layers and apply the mask to the visible layer using sg-copy-mask-to-layers.scm
3. Apply the layer mask to one of the layers with the script sg-apply-layer-mask-all-layers.scm

Obviously there is some user intervention between these steps, deleting layers, selecting layers. How to batch that I do not know. The scripts attached, zipped. Unzip and put in your scripts folder. Maybe you can use bits of the code to re-draft your batch procedure.

I can just get that into 1 minute for imgur:  https://i.imgur.com/ghBxhvm.mp4

best of luck.