Why does it look like it has an internal structure? Also, why does it seem to radiate light when it is supposed to be light itself?

The image circulating from that post is a 2024 visualization from University of Birmingham physicists Ben Yuen and Angela Demetriadou, published in Physical Review Letters. It shows the calculated shape of a photon emitted by an atom on a silicon nanoparticle. Under those conditions the intensity map looks lemon-shaped, with banding and radiating structure. It is not a photograph. You cannot snap a picture of a single photon the way you photograph an object. Detecting a photon absorbs it, and photons do not bounce off other photons. The figure is a mathematically generated map of the photon’s wave function — where you would be likely to find it if you measured many identical emissions. The researchers themselves describe it as a by-product of a new way to calculate light–matter interaction, not a camera capture. Also, photons don't have onlines like this.