GIMP script-fu to add a "x" pixel border to image(s)

Been trying to make a simple script-fu to use ‘scale-layer’ to reduce an image(s) by x pixels on all sides (e.g. add a “gutter” and save back to the original size. Example: 128px X 128px .PNG file, add a 20px gutter to image. The new file should have the original image scaled down to 88px X 88px and saved back to 128px.
This seems like it should be easy, but I don’t really have the time to waste to learn scripting just to batch convert one directory of icons.
FYI: I’m using Windows

You can use BIMP the Gimp batch plugin.

A Windows installer here: BIMP. Batch Image Manipulation Plugin for GIMP. | Alessandro Francesconi

…and it might go like this: 50 second demo:

edit: thinking about it, icons ? you might want to use interpolation None for the resize operation.

edit: I must stop thinking of snags. If you need a transparent border then a subterfuge using the old drop shadow. zero offsets / 20 radius / 100 opacity / allow resize.

Thanks for the BiMP tip! It works great. I ended up modding the addborder script to add a layer transparency option for the border.

Yes, I ended up doing the same when I saw the legacy drop shadow left a bit of a ‘glow’ even with 100% transparency.