gonna keep banging this drum every time this comes up:

When physicists say "observe", they actually mean "measure". And to measure a photon of light, you have to interact with it somehow, there is no passive way to do so.

The post's header image implies that the interference pattern goes away just by looking at it. If that were the case, we would never see the interference pattern, never know it was there in the first place! In the actual experiment, they put a sensor at one or both of the slits. But to "sense" a single photon, you have to interact with it in some way. Otherwise you wouldn't know it was there.

Again, this is where the language trips us up. Rather than "sensor", would really be more accurate to say they put a photon-touch-er at the slits.

So, what we actually get is "Touching the photon changes the photon's behavior." The universe doesn't magically infer when we happen to be looking at it, there is no spooky action-at-a-distance!

The uncertainty principle has increased ... my uncertainty.