The double slit expiriment demonstrates the duality of the nature of a photon: that it’s both a wave and a particle.
When a photon is “observed” (or detected) it has the properties of a particle. However when it’s travelling it acts like a wave and can demonstrate interference patterns with other photons.
So when you pass photos through two tiny slits, instead of them just passing right through like a particle, they interfere with each other and when the wave pattern collapses when it is observed on the wall, you see the interference.
That being said, I don’t think this cartoon makes sense. I get what they are driving at, as they are saying it acts differently when not observed, but this is not what happens. Also this isn’t a ln experiment that deals with observation forcing an outcome, but as I noted it’s about the duality. Additionally, the wave pattern on the top is what you would you observe when looking at, so I’m not sure why that is what it would be like if you were looking away.