Probably a very dumb questions, but I want to replace the background pictures on my home page. One pic is the Home_9_img_1 the other is called Home_9_footer_img.
Footer image can be changed under Appearance > Theme settings > Styling > Footer Background Image.
Homepage section images can be changed by editing your needed page and in page builder clicking on Section element. Then open Background tab and there should be Background Image option which you can change.