Photo manipulation, simply propaganda. Sergei Eisenstein (a famous Soviet movie filmmaker) was in charge of manufacturing and manipulating evidence for the Nuremberg Trials. He could have easily doctored and created many such photos and even videos. It's called the magic of television.

Also the Soviets themselves were doing huge amounts of medical experimentation on their own people via the starvation and genocide. They were the ones who introduced water fluoridation to their population. If you're not aware, they were renowned for having many medical breakthroughs and lots of experimentation and data about longevity for decades. They made these discoveries by experimenting on live people. They merely shifted the blame to the Germans instead. The real victims were the Russians and Jews slaughtered by Stalin. The Germans were never guilty of these accusations. They were just a scapegoat.