• Check which thumbnail is used by a file with gio info -a 'thumbnail::path' <file.png>

• Here a script to generate shared thumbnails for a specific folder: (AS well linked in the UCA Wiki)
• Start tumbler from source with debugging enabled
  • Build & install tumbler
  • killall tumblerd
  • rm -rf $HOME/.cache/thumbnails/*
  • G_MESSAGES_PREFIXED= G_MESSAGES_DEBUG=all /usr/local/lib/tumbler-1/tumblerd
• Monitor tumbler DBus 'Ready' signals:

dbus-monitor "interface='org.freedesktop.thumbnails.Thumbnailer1',member='Ready'"

• Monitor tumbler DBus 'Error signals:

dbus-monitor "interface='org.freedesktop.thumbnails.Thumbnailer1',member='Error'"

• Monitor tumbler DBus 'Finished' signals:

dbus-monitor "interface='org.freedesktop.thumbnails.Thumbnailer1',member='Finished'"

• Monitor tumbler DBus All signal:

dbus-monitor "interface='org.freedesktop.thumbnails.Thumbnailer1'"

• Check some mandatory attributes of the thumbnail via identify -verbose <thumbnail.png>
  • Thumb::URI
  • Thumb::MTime
• Checksum:
  • The checksum used for the thumbnail name is build from the absolute URI of the file to thumbnail. It can be generated like this:
  • Command:

echo -n file:///home/my/photos/me.png | md5sum

--> c6ee772d9e49320e97ec29a7eb5b1697.png

• Detailed documentation can be found here: https://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html#CREATION