Do you know a webpage appearance comparator?

Question

I need a tool to compare the design of a website, I do not want to compare the HTML code only, but the output design.

Is this even possible? also is there any openso

Answer 1

Solution: “compare web pages” tool. (“We've been doing it since 1999. It's free.”)

Example output (comparing pages for TP-Link USB hub model UH700 and UH720):