We are worried about why options to add an image for contact section background is not working.
Now, if you want to change the image via child theme, you need to copy widget to the child theme and you need to edit some line of codes.
You must know some codes of parent and child theme. In child theme, ge_stylesheet_directlry_uri instead of get_template_directory_uri. So first check codes works.
So, we recommend you to check options meticulously instead of working with codes.
Let us know