GIMP Flatpak Installation on Ubuntu 16.04 – How to Guide

For scripts and Python plugins, a simple solution is to put them in some plain directory (outside of the flatpak packaging) and use Edit>Preferences>Folders>{Scripts|Plugins} to add them to the directories checked by flatpak Gimp (this is also a good way to share them between your Gimp 2.8 and Gimp 2.10).

Binaries are a different matter, binaries for 2.8 may not work with 2.10 (and in many case will have to be at least recompiled to take advantage of the new bit depths in 2.10), and the new binaries may have dependencies on libraries that are only available in the flatpak environment.

There is also the (rare) occurence of a Python script that depends on a python library which isn't part of the Python installed in the flatpak environment (which isn't the same as your system Python).

These problems are at the core of many open issues.

To run Gimp:

flatpak run org.gimp.GIMP "$@"

But AFAIK there is a desktop file somewhere, I have a ~/.local/share/applications/org.gimp.GIMP.desktop with:

[Desktop Entry]
Categories=Graphics;2DGraphics;RasterGraphics;GTK;
Comment=Create images and edit photographs
Exec=/usr/bin/flatpak run --branch=stable --arch=x86_64 --command=gimp-2.10 --file-forwarding org.gimp.GIMP @@u %U @@
GenericName=Image Editor
Icon=org.gimp.GIMP
Keywords=GIMP;graphic;design;illustration;painting;
MimeType=image/bmp;image/g3fax;image/gif;image/x-fits;image/x-pcx;image/x-portable-anymap;image/x-portable-bitmap;image/x-portable-graymap;image/x-portable-pixmap;image/x-psd;image/x-sgi;image/x-tga;image/x-xbitmap;image/x-xwindowdump;image/x-xcf;image/x-compressed-xcf;image/x-gimp-gbr;image/x-gimp-pat;image/x-gimp-gih;image/tiff;image/jpeg;image/x-psp;application/postscript;image/png;image/x-icon;image/x-xpixmap;image/x-exr;image/x-webp;image/heif;image/heic;image/svg+xml;application/pdf;image/x-wmf;image/jp2;image/x-xcursor;
Name=Gimp 2.10
NoDisplay=false
Path[$e]=
StartupNotify=true
Terminal=0
TerminalOptions=
Type=Application
Version=1.0
X-Flatpak=org.gimp.GIMP
X-Flatpak-Tags=stable;
X-GNOME-Bugzilla-Bugzilla=GNOME
X-GNOME-Bugzilla-Component=General
X-GNOME-Bugzilla-OtherBinaries=gimp-2.10
X-GNOME-Bugzilla-Product=GIMP
X-GNOME-Bugzilla-Version=2.10.2
X-KDE-SubstituteUID=false
X-KDE-Username=

The real installation is in /var/lib/flatpak/app/org.gimp.GIMP/

If you are used to "native" Gimp, be aware of some restrictions:

• the "recent files" are not shared with other apps in the system
• the /tmp directory as seen by Gimp is remapped to a directory specific to flatpak, so you cannot share files through that (which is unfortunately required for some apps, such as web browsers)
• the Python runtime is specific to Gimp
• the Gimp profile is buried in ~/.var/app/org.gimp.GIMP/config/GIMP/2.10/
• you may want to use Edit>Preferences>Folders to setup folders in more "visible" directories for your brushes, patterns, scripts and plugins
• compatibility with the popular plugins (GMIC, resynthesize...) isn't clear. It seems this requires flatpak versions.