If you share a video on email or social media, the link will appear as an image of the video with a play button. To get as many clicks as possible, choose an image that attracts the recipient's attention, e.g., a picture of you smiling and holding up a note with the recipient's name.
Select an image for the video
Select a video and tap the image icon on the video to select a new thumbnail image. You can choose to upload a picture or create a new one.
Press "Select from video" to select an image from the video. Play the video and press pause on the video image you want to select, then press "Capture".