This icon has started showing up on all video file thumbnails.
How do I get rid of it please
This is the play button indicator requested several times by different users - it allows you to quickly tell if a file is a video or an image - especially important in the Viewer.
This enhancement was introduced in the 2023.3.4 release and is documented in release note #02054
The released note also explains how to turn this off: If you don't want this, you can disable it via Edit > Preferences > File Window: Window > Show thumbnail overlays.
I really recommend reading the release notes I provide for each release to learn about new features and changes.
This is the only way for me to communicate with users about new features, changes and bug fixes.
I know these are busy times, but a minute or two spent with reading the release notes is time well spent.
IMatch even opens the release notes in your browser after installing a new release!