Need to update background image for template

I wonder how do I change the wording of this template.
Can you help me?

This form was created by another user, not by JotForm. The background is an image, not text so we can't readily update it. Here's the URL of the image for reference:

http://mohammadali.se/contact/bg.png

It can be updated with PhotoShop, or a similar online tool such as ipiccy.com.

Once you have a revised background image the updated version can be uploaded to your own website.

Next, use our inject CSS feature to include the updated background URL. Please see this link for more info:

https://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes

Specifically, you'll want to update the URL for the background value.

Let us know if you have further questions.