By default, the background image is displayed in tile. You can changed that to full screen with the help of some custom CSS coding. Here is how you can display the background image of the form in full screen:

1. Go to the Settings → Themes section of your form and click on the Use Custom CSS link.

3. Enter this code and hit Apply:

body { 
background-size: 100%; 
}

The background image will now be displayed in full screen.

You can disable the form frame in the Background & Form Frame subsection to make the design of your form look more clean. Unfortunately, if you embed the form on a webpage, the background image will disappear.

For more dynamic web forms, upload a gif and amuse your visitors with some live animation in the background of your form. Here is an example.

You can adjust the position of your form on screen by using the margin-left or margin-right property with the assigned value in pixels (e.g. margin-left:450px;).