You cannot pass HTML in a CSS document it's simply not possible. Your best bet is to consider looking at Javascript but of course you would need to edit the HTML header to include a JS script.
But again, this isn't changing the html. So if you already have that img in your file you'll need some js added to the head to change it. and if that img doesn't have an ID or class unique to itself it will be difficult to select only that img.
Is it possible to add a URL path to a image through CSS only? I can't change the HTML as it would break future updates to the page....
That will set the content of all p tags to "your.gif" Just use a class or id selector to specify where to replace.
HTML:
now I want to add a URL to that HTML, but only from the CSS file. I can't edit the HTML.
But this is easy to bypass. Just put an empty span inside a div and set the image after the span.
Like this
But again, this isn't changing the html. So if you already have that img in your file you'll need some js added to the head to change it. and if that img doesn't have an ID or class unique to itself it will be difficult to select only that img.