WebDAV Specification thumbnail/preview file image

apache nginx webdav

My answer is brief. There is no standard for this.

apache nginx webdav

As a workaround if you control both the WebDav server and client then you can:

Create a Thumbs.db file and download it. Personally I like this idea because it's clear, well known and already used in Samba
Add an additional tag (with own namespace) into response with thumbnail or a separate call REPORT as proposed here https://lists.w3.org/Archives/Public/w3c-dist-auth/2009AprJun/0012.html

Nextcloud/OwnCloud discussed creation of a separate Preview API but this looks like totally not related to WebDAV

CodeHunter