Background image unable to change

Do you mean the slide images that comes on the homepage ? It is not the background image it comes from the slider (revolution slider or layer slider). So change the images from there or create your own slider images and connect it in the homepage page builder section. Let me know if I misunderstood your query. Also share the screenshot of the issue for better understanding.

Can you please share more details with screenshots from where you are trying to change the image and where you want the background image to be changed? Please also share your admin credentials to check the issue more closely . Share proper steps to help us in resolving this issue . Can you please also share more details on this  : "  But the theme overrides the background image  "  . Latest modern theme you can download from here : https://wplms.io/support/knowledge-base/modern-theme/ You can also manually upload the modern theme via ftp or cpanel . Just upload the wplms_modern.zip file in your wp-content/themes/ folder and then unzip it .