While Braiv Player automatically creates a suitable thumbnail for your videos, you can upload your own images easily...heres how:
Select the video you want to add a thumbnail to.
2. On the left-hand corner select Details.
3. On the lower-right corner, click the '+' icon.
4. Your File folder will pop up, select your file then click Upload.
5. Instantly, the Thumbnail will be set. Click Save Button on the upper-left to save the changes.
6. When you get back on the Video Library, you'll see that the video thumbnail is already change for your video.
Additional Info: When you select the video file you will also see the Thumbnail on the left side as shown below. You can click on Preview on the upper part to see how it will look like in the Video Player.
Here is what it will look like in the Video Player.