Are websites aware when thier pages contain third party pixels?

I only just learned about "pixels" aka the 1px by 1px or even 0px by 0px images that trackers will put on websites, so they can glean analytic data from any and all IPs that are active on those sites. It's able to bypass the sort of blockages installed surrounding cookies. From what i can tell, it seems not to be regulated much at all.

I learned about them from an article saying how TikTok was expanding it's use of …

aware party privacy third websites