I do not have a MacOS VM anymore, so I cant demo the plugin installation. Copying a file
something.py into the plugins folder
/Users/MyName/Library/Application Support/Gimp/2.8/plug-ins should not overwrite it. I can't say what you are doing wrong but you are.
One thing I do recall, sometimes that plug-ins folder is not created and you need to make one yourself, then make sure the path in Preferences -> Folders -> plug-ins exists.
Edit: Going back a few years but this one
https://youtu.be/CHHqlHdmQ0o gives a bit of info on installing plug-ins and scripts. It does show Gimp 2.10 but 2.8 is just the same
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More generally, it is a plugin, make sure it is executable.
It does use ImageMagick (IM)
http://www.imagemagick.org and you need an old version 6 The current version 7 uses a different syntax 'convert' becomes 'magick'
40 second demo in linux kubuntu 20.04, Gimp 2.8.22 / IM 6.9
https://i.imgur.com/TQtESgN.mp4There is an old script
sg-save-pdf-multi.scm works but with limitations, needs each page open as an image and tedious when there are lots of pages. I will attach it in case anyone wants a try-out. another 40 second demo.
https://i.imgur.com/lV6GruN.mp4If you have IM installed, you can make good PDF's by command line. This for IM 7 Using jpg's give a smaller PDF.
magick name-1.jpg name-2.jpg......name-n out.pdf
..and some comparisons on file size:
Attachment:
pdfs.jpg [ 95.06 KiB | Viewed 1787 times ]
That last one, a bit strange in my experience. Gimp is/was renowned for making over-large PDF's. I wonder if the devs have finally tweaked it with Gimp 2.10.32 ?