The aspect ratio for images, backgrounds and feeds can now be set.
Right click on an image, background or feed
Select the Set Aspect Ratio option. The options available are Automatic, Maintain, Stretch or Zoom.

You may also change the aspect ratio for a background assigned to a song in the schedule.
Right click on a song in the schedule.
Select Set Aspect Ratio.  The same options will be available as with images, videos and feeds.

A background can be edited to use a specific aspect ratio each time you use that background.
Click on the Background button.
Click on Options.
Select the background you want to modify.
Click the modify button.
Select the Aspect ratio from the Drop down list.

Aspect Ratio Settings Definitions:

Automatic - For Images, Videos and Feeds, the automatic setting will  Maintain the aspect ratio.
For Backgrounds the automatic setting will stretch the background to fit the screen. 

Maintain - Keeps the original size of the video, image, feed or background.

Stretch - Stretches the video, image, feed or background to fit the screen.

Zoom - Zooms in on the video, image, feed or background cropping the edges.