measure/record pixel coordinates

[Ofnuts]

I wrote that script for Gimp 2.6 IIRC, and I recently used it in 2.10, so with 2.8 you should be fine.

• You definitely need Python support in Gimp, so first check if you have a a Filters ➤ Python-fu ➤ Console entry in the menu (bottom of Filters, next to Script-fu. If not, IIRC your distro has a gimp-python package that you can install with apt or your software manager.
  
• Once you have the Python support make sure that the .py file is marked executable
  
• If still no result, start Gimp in a terminal and watch for error messages