In addition to running scripts designed for the GIMP you are also able to run many 3rd party Photosop Plugins within the GIMP thanks to PSPI. Originally written for the Windows version of the GIMP it has also been ported to Linux.
I have been using the standalone version of the PTLens application for a couple of years for fixing distortion within images. I gave the Plugin version of it a try using PSPI. It seems to work well without any problems.
Developers can add additional functionality to the GIMP via scripts. Many scripts are available for download from the GIMP Plugin Registry.
They often come in two different versions, Script-Fu or Python. The Python versions generally provide enhanced functionality over the Script-Fu versions.
Note: To find scripts in the Plugin Registry search on keywords.