I want to change my background but every time I change the background and save it then preview the form it doesnt stay? How can I fix that ?

Hi,

I needed to apply a new theme to the form to overwrite the background but you should be able to remove the gradient.  Even removing all the CSS from the form would not allow me to remove it:

https://form.jotform.com/60134985514962

Clone it to your own account and you will be able to edit the background of the form and the background image without issue:

http://www.jotform.com/help/42-How-to-Clone-an-Existing-Form-from-a-URL