Hi,
Actually, that is not the case. Some transforms like cropping or resizing image are made to all images for instance for computational reasons.
But other transforms like, affine, colorjitter, etc can be done randomly which in this case, you provide p=your_desired_prob to ensure transformation is only happening with probability of p. So, there p-1 of augmented images of that transform are original images.
For instance, you can see the docs of RandomApply.
Bests