Editing or Cropping an Existing Thumbnail Image
You can edit or crop an existing thumbnail image.
To edit or crop a Thumbnail image:
1. 
Click the Edit Thumbnail image icon.
The Edit Your Thumbnail dialog box opens showing all of the previously imported images that are available to you.
2. (Option) If you only want to display a portion of the image, click and hold the red corner markers to drag in or out to adjust the cropped area displaying what you want to display for the image.
3. Select the Aspect Ratio Selector to crop the image for each specific aspect ratio and determine the orientation of the image. Options are:
16:9 landscape
9:16 portrait
1:1 square
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.
4. Click Save to save your changes.
