Generative models does not work like that, if it were so, how do you explain that I can generate a picture of a purple six legged cat throwing lasers from the eyes in space?

In a very very very simplified way, the models are trained that from noise it de noises it until the image is “restored”. A part of the model learns to remove noise until a drawing of a child is restored, another learns to restore the image of a drawing of a nude woman. Basically you say to the model that from noise it has to restore the drawing of a nude child it combines the two proceses (also it is trained to combine things in a way that makes sense).