Selecting an Existing Image or Uploading an External Image
You can select an image that has already been imported as your thumbnail. Or, upload a new image.
To select an existing image or upload a new image:
1. 
Click the Choose an External Image as Thumbnail icon.
The window opens showing the gallery of existing (previously imported) images that are available to you.
2. View the images available to you, and do one of the following:
Select an image you want to use by clicking the checkbox in the upper right corner of the image. The thumbnail image appears in the Clip Details window. Go to Step 7.
Upload a new image to use by clicking on the Upload (Cloud) icon.
The Import Files dialog box opens. Go to Step 3.
3. Either drag and drop a file into the window, or click Upload a File.
If you selected Upload a File, the Open dialog box opens.
4. Navigate to the file you want to use, select it, and click Open.
The File opens in the Imported Files tab, and the Clip Details area.
5. Adjust the size of the image by dragging the corners.
6. When you have located the image you want to use, click Save.
The file will be added to the video clip, as well as to the gallery with the other imported images.
The location of the image is set in the original image file. Images should be created with a frame size of 1280x720 pixels, or other 16:9 aspect ratio. Save Images with a transparent background in PNG format for best results.
7. (Option) To add additional previously imported thumbnail images or upload new thumbnail images, repeat this procedure.
