Hello- not a pro here, but just messing with various MP4 video clips. When clip is viewed by a file manager like Windows Explorer set to display thumbnails, a frame from the clip is shown. I can add or subtract frames at the beginning of the clip and a different thumbnail will be displayed in the file manager. Is there a way to nail down the thumbnail so the frame I want is used?

I Googled this question and didn't find anything but anguish and agony!

I am using an older Windows Movie Maker. I just realized it's been discontinued for some time. Is there an editor that has the capability of setting the thumbnail? Since I do this not too often, something free or cheap would be great.

I've also been taking tutorials on Creating a Cinemagraph in Photoshop on Lynda.com. Could I set the thumbs in this application?