What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
You can do it by going to the Designer tool, on the top toolbar click on the Designer icon:
Then click on the option "Background Image", here are two options, one is to set up a background image to the entire page while the other sets the background to the form only:
Once you click on the Upload button, you will get a wizard where you can choose an existing image or upload your custom image:
Setting a "Page Background Image" will result on this:
Setting an "Form Background Image" will result on this:
Hope this helps.