You either missed the context or misread the post. Pixel tracking refers to using any kind of beacons to send back data (originally images but now also JS tags)

You either missed the context or misread the post. Pixel tracking refers to using any kind of beacons to send back data (originally images but now also JS tags) and there are many ways to optimize. This has nothing to do with lazy-loading image tags. This browser-native functionality doesn't add any kind of new tracking, and pixels are never lazy-loaded anyway because they need to be fired as soon as possible to ensure data capture. Nothing about this new API changes anything for ads.