- Is it possible to display thumbnail views instead of just the list view, especially for media files?
No, the views can’t be changed in websharing.
- Can filters be saved?
I’m not sure what filter you’re referring to, but no smart groups cannot be created, neither manually or by saving a search, in websharing.
- What determines the default layout of the text or markdown notes? The tiny serif font is not really nice by default. How can this be adjusted?
A screen capture would help.