Is it though? I know standards are important, but what does it really cost a browser maker to be able to resolve paths with backslashes? Similarly, is it really that big of a deal to support background-position-x and y? The prime example of something should have been a spec from the beginning.

I stand corrected!

Nor in Opera 12.

The wrong slash has been used in the URL. It's supposed to be a broken image.

There's an invalid URI within the IMG starting with http:\\ instead of http://. A mistake a beginner designer who's used to Windows directories would make. Some browsers like IE helpfully 'fix' this mistake and accept it so the beginner designers have no idea they're writing broken code. Other browsers like Firefox interpret it as written and show it as broken.