Open Source Document Management System | OpenKM

Been trying to get a preview of the images to work for the last day but cant find how to make it work,

Already:
installed Imagemagick
Ghostscript was already installed
installed Libreoffice too
installed docker,

ran it:
sudo docker run --name openkm -p 8080:8080 openkm/openkm

anything else I need to add?
thanks

Does imagemagick and Libreoffice go inside the Docker image or do they go outside?

BTW, uploaded a PDF and it works.
Uploaded a PNG and it doesn't work.

noticed swftools path differs from docs, instead of /etc
Docker path says
system.swftools.pdf2swf String /opt/openkm/bin/pdf2swf -f -T 9 -t -s storeallcharacters ${fileIn} -o ${fileOut}

So far, PDF and TXT files show preview