If you wish to perform a screenshot on your WAGO HMI, you can use this Docker command :
docker run -it --rm -e DISPLAY=$DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix -v /tmp:/tmp/screenshot quenorha/screenshot
The image is just a few megabytes.
The screenshot will be store in /tmp folder.
Could be interesting for after sales support for instance.