Do it work if you use the File>Open menu in Gimp or is it just a matter of associating Gimp with the image files?
If File>Open doesn't work, go to Edit>Preferences, open the Folders section, and clik on Plugins. On the right side you should have two directories listed, one being in \Users\{your_id} and one in C:\Program files navigate to the latter with a file explorer, do you see files named file-something.exe, or file-something-save.exe or file-something-load.exe?
If File>Open doesn't work, go to Edit>Preferences, open the Folders section, and clik on Plugins. On the right side you should have two directories listed, one being in \Users\{your_id} and one in C:\Program files navigate to the latter with a file explorer, do you see files named file-something.exe, or file-something-save.exe or file-something-load.exe?