Set Your Own Video Thumbnail
HTML5 Video Player allows you to set your own video thumbnail and poster image manually and easily.
To change them is very easy. Go to drag and drop your source video clips into the HTML5 Video Player. You will see the added video clips displyed on the left panel. Click to select the video you like to edit its thumbnail, then click the Edit button above the video thumbs list or double click a video to open the Preview & Video window, see below.
You can play the video or drag the slider to get a video frame you like, then click the Screenshot button to capture the screen and this screenshot captured will be used as the video thumbnail and poster frame or poster image in your final HTML5 video player.