At least writing Python script for ImageJ is much easier than for GIMP. Besides, the GIMP Python-fu specification is in flux. Writing way of Python script will be drastically changed in GIMP Ver. 3, and nonetheless there are no instructions for that yet. Therefor I think I have to write ImageJ script for GIMP image editing.
In link below, Here is an example of ImageJ script for editing in GIMP.
It is a making tool of spot removal mask.
If you are interested in ImageJ script for photo editing, please try it.