How do I get the background and foreground to fill the screen?

[De_bug]

Working on a video that has looping animation of a skeletal unicorn walking, I added in the background and am using zoom to make the background scroll across, same with the foreground. But there's a gap between the top and bottom of the background/foreground. 

As the title says how do get the images to fill the screen? or is there a better way to make the background/foreground scroll that I'm just missing?

relevant images/screenshots

 

[borate]

Try scaling up the foreground and background, to fill the screen.

If you share the project, someone will scrutinize it.  The process is easy, quick and can be done privately.  Just follow these steps one-by-one...

•     Back up --- With your project on the timeline, click on MENU at the top-left.  Click FILE|BACK UP PROJECT FILES TO FOLDER.  Choose a folder and SELECT FOLDER.
•     Upload ---  Use a free server - Google Drive, MS OneDrive, etc.* - to upload the saved, numbered FOLDER.    Do NOT upload the individual VPJ or export file. 
•     Get link --- Get a public link.  Right-click the file and click SHARE. When using Google Drive, if necessary change "restricted" to "anyone with the link can view" 
•     Share ---     Click COPY LINK | DONE.  Paste that link here, or click the folder at the top-right of this forum to message it privately to me.  It won't be shared.

          *    Before uploading, right-click the folder, click PROPERTIES.  Look at the File Size to confirm that it's not too big for the free space on the server.