Fun fact: Gas chambers are often used to kill pigs. You can hear their screaming from outside the facilities as the gas burns them to death from the inside out.
This is common practice.
It is plenty likely the victim in the picture whose mutilated corpse is very disrespectfully converted into sewage by now was gassed to death.
Nobody has said anything about the Holocaust or the Jews. This is standard practice of killing pigs.
If you want to have a conversation about this topic, I would like to highlight that we are animals too (just a different species) and I don't think there is any moral difference between our species and dogs or pigs when regarding killing, even when I know about our differences because at the end of the day we are just individuals we clear interests in avoiding suffering and death, and byproducts of pigs are just unnecessary to consume and cruel to get.