Why are there backslashes at the beginning of the counter id img src url?

You're right this is odd. It turns out that \\ or // are both treated as protocol relative urls by chrome - but // is per the spec so we should change this.

FWIW \\ also works in Firefox and Safari so I think this is just a normal bug and not a ciritical.

Automatically closed - issue fixed for 2 weeks with no activity.