I did a migration of a subsite from one host (on a multisite) to another host WP single install and some elements didn’t come over smoothly to the new host. One element was the header image. When I tried to use the Customizer to add a new header image, I got the following error. It’s not allowing an upload from my computer for the header upload.
Call to undefined function weaverx_use_inline_css()
FYI: the multisite was set up with the xtreme plus. I then tried to add the header image through the CSS, but I didn’t get that right either. Here is what I added in the Custom CSS box:
Many things wrong with the CSS, but before mentioning that, I would want to get whatever is causing the error fixed, as who knows whatever perverse effects it is having.
@weaver may be able to offer a clue as why you are getting that error.
As for the CSS, adding a background image to an image would not do anything as if the image is actually there it would be over, and if the image is not there (what your post is implying), there is nothing to apply it to.
There is also a double quote that is invalid and the Image URL does not look right
You could add a background image to the header area with the rule below, but would probably need to force a height on it to as if the header is empty the background will not show
After checking that you have the latest versions of everything, you may want to save your settings and download a backup copy, then switch to a different theme, delete all weaver theme and plugins, then reinstall clean version from WordPress and from a new download for Plus.