thumbnails

[TomTasche]

I remember we talked about this before but I forgot the conclusion: how could we generate thumbnails for documents? would we render the documents ourselves and create an image for it or is the pre-generated thumbnail included in the document itself already? @andiwand

[andiwand]

there is a thumbnail.png inside which would be easy to use. i think it's a kind of recent addition. if it is not there we would have to render html to an image to fully complete this task.