Why do VLC media player show icons on video files?

I have vlc media player and with some of my video files some will have the vlc icons while others will show the screenshots of the video?.How to bring those files with icon to show the screenshots instead?

?2021-02-26T21:46:10Z

it is not VLC that shows the video, but Windows. it only reads formats it is programmed to recognize.

Richard J2021-02-26T19:26:35Z

It is because it is the Media Player you have chosen to watch your video's with. It is set as your Default Video player. If you were using Windows Media Player as default, it would display it's icon instead. 

To change the icon

Start
Enter Default apps
Video player
Make change here

dewcoons2021-02-26T18:43:53Z

Different types/codex of media files have different information in them.  Some types of media files have information needed for a thumbnail pictures.  Others do not.  If there is no thumbnail available, VLC will show its icon instead. The only way to get a thumbnail would be to convert the format of the media file to one that includes a thumbnail.