From the docs:
All pre-trained models expect input images normalized in the same way, i.e. mini-batches of 3-channel RGB images of shape (3 x H x W), where H and W are expected to be at least 224. The images have to be loaded in to a range of [0, 1] and then normalized using
mean = [0.485, 0.456,0.406]andstd = [0.229, 0.224, 0.225].