Updated, consolidated and simplified version of Mario Crippa's 2013 GIMP Instagram plugins. Free to download and use.
This GIMP plugin is now available for both 2.10 and 3.0 versions. It pulls most of the original Instagram effects into a single file. Deprecated elements in the originals have been replaced with their current counterparts. Some of the original effects have been simplified and changed to make the plugin more manageable. Borders have been removed entirely and some of the vignettes have been simplified.
The Gimp 3.0 version contains a re-usable workaround that enables the Gimp.Drawable.curves_spline method to be used in non-linear space.
From a user standpoint: I often used the original version of these plugins to help when painting landscapes from photographs. Some of the effects were extremely helpful in breaking free of the typical green palette of the Virginia piedmont, and they changed the way that I used photography in my artwork. I hope that these new versions will, in turn, be of help to others.
To install, download the file and place it in the appropriate folder location. You can find this by selecting Edit/Preferences then navigating to Folder->Plugins from the GIMP menu. If you have not already done do, it is much easier to find these folders if you make them visible — in Windows, you can do this from the menu bar in File Explorer.
Install the GIMP 2 plugin directly in this folder. Note that the GIMP 3 plugin must be installed inside a sub-folder with the same name as the plugin. The installation location will look something like those shown below.
Windows:
C:\user\<username>\AppData\Roaming\GIMP\2.10\plugins\gimp_instagram.py
C:\user\<username>\AppData\Roaming\GIMP\3.0\plugins\gimp_instagram\gimp_instagram.py
Linux:
/usr/<username>/.config/GIMP/2.10/plugins/gimp_instagram.py
/usr/<username>/.config/GIMP/2.10/plugins/gimp_instagram/gimp_instagram.py
And that's all there is to it. Open GIMP and you're now ready to go with your new plugin.