The link you decided not to follow gives a lot of context. Although in French, which I do not speak.
These people weren’t murdered at Dachau. They are being cremated there, after dieing aboard the prisoner transport train from the Royallieu-Compiègne internment camp.
The German Wikipedia about the Sonderkommando photographs describes those as the only surviving photos taken by prisoners inside the camps.
Dinkleberg!!!Russia!!!