Manually set video preview

[HerrAugust]

Checklist

• [X] I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• [X] I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• [X] I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• [X] I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• [X] This issue contains only one feature request.
• [X] I have read and understood the contribution guidelines.
• [ ] I optionally donated to support the Fossify mission.

Feature description

Video preview image can be manually set for videos through the integrated Video Editor.

The video preview image shall be visible in the screen containing all the images and videos.

Why do you want this feature?

Without this feature, people are forced to watch the video to remember what it is about.

Additional information

No response