> This image of galaxy cluster SMACS 0723 has been constructed from blue, green, and red filters aboard Hubble, along with four infrared filter views of the cluster’s central regions. Hubble viewed this object to wavelengths of ~1600 nanometers; [1]
1. Those are diffraction spikes that reflects the structure of the mirror, which is composed of hexagonal elements.
2. That is background galaxies that are distorted and heavily magnified due to gravitational lensing, gravity from a foreground galaxy can bend the light just like a lens (the sun bending the light from stars during an eclipse was an early test of general relativity just after WWI)
Update: Hi resolution image also available here https://esawebb.org/media/archives/images/original/webb-firs... (4537x4630, ~39MB)