The URL tracking language is way too vague in the revised regs. If it means I have to record that a certain set of pics is on 123.com then it's no problem. If it means I have to list
http://www.123.com/images/1000234/001.jpg, http://www.123.com/images/1000234/002.jpg, etc, then it approaches impossible. Plus, consider the php based sites that are dynamically generated. This is another great example of the government trying to regulate an industry that isn't understood by any of the regulators.
I'm waiting to see what survives and makes it into the revised regs, but there is some potential for disaster there.