Is there any picture viewer alternative for Gwenview, preferably qt, for Plasma environment, that displays only picture files, not any other like pdf content, video. Or is there any that allows to configure what extensions are to be displayed?

I dislike Gwenview since it has been all multimedia files viewer without options to disable some files extensions.

How about qimgv ? Imo it's one of the best. Nomacs too ain't too bad but personally I prefer qimgv.https://imgur.com/a/MrgZoXZ
Edit: Qimgv does show video as a thumbnail though.