No, my answer is correct. If you remove the CSS line with an empty string as the image source, you'll see this change immediately in your browser's Network tab.
An empty string means the current document will be loaded. This has always been true in CSS url() and HTML src/href contexts from the beginning of these technologies. Nothing unexpected here.
Please mark my answer Correct when done.
That is absolutely fascinating. After I uploaded the new HTML to the template, approved it, and then approved the newly created draft on the instance, it worked.
Yep... need to look under the hood to see what resources a browser is actually hitting.
[a] resources successfully fetched and rendered and [b] resources that cannot be fetched aren't the whole story. There are also [c] resources that are fetched from a remote server but are invalid for the element they're supposed to populate, so they're thrown away, but the hit still remains.
I explored a related case here a few months ago: Flop-timized: Marketo LPs and the case of the 300KB favicon
And how do you make custom URLs? I can't seem to change the automatic one that was generated.
Change the pagename under
Landing Page Actions >> URL Tools >> Edit URL Settings
But I was referring to the LP domain, which is set up in Admin (and in concert with your DNS admin).
I don't have access to that as my account is not an admin level account.
You must find out what your LP domains are to test with those. Because of the way cookies work, testing analytics with the built-in *.marketo.com domain will not work as expected (but this isn't related to your current question).
Also, please move this thread to Products before marking my answer correct. ("Central" is supposed to be for general, non-product-specific discush.)