[Zodler]

On the left pane where we see all the files in a list mode, it would be great also to switch that to a Thumbnails View where we see only the covers.
The right pane that gives the details stays. It doesn't change. Something like this in Kodi:

[mlaggner]

tmm is a media manager and no media center like kodi. Having that said it is not our intention to make such a view, because this is not in the focus of the app...

from a technical view: we're build on Java/Swing and managing that much images on one single view (imagine users with several thousand movies) would need too much memory and CPU performance to render.

If you just want to access your media without Kodi from such a view, create/use one of our export templates (HTML/CSS/JS can handle this).. Inside tmm you won't get this

[Zodler]

It doesn't have to be a media center to show thumbnails. Many catalog software can show thumbnails. It's a fast way to browse a movie collection and recognize what a movie is about than reading a list. So it is a valid feature.