Hi there!
Sorry for your experience.
It seems the template has overrided addon for SP Page Builder. Which addon you are facing problem with to change image?
It will be better to contact with your template provider about it. They are supposed to help you in this case. If not, then you can rename the site.php file of overrided addon folder, then the original file will be loaded and problem should be resolved.
Sample path for the overrided addon's site.php file:
templates/shaper_YourTemplate/sppagebuilder/addons/addon_name/site.php
Best Regards