mayool:

which tensor should be fed into the network?


If you want to just scale your input in range of [0, 1], transforms.ToTensor will do the job. If you need to compute z-score you can use transforms.Normalize.
As you have mentioned you are using pretrained network, you may want to normalize them. Unnormalization is used for viewing the transformed images or when your model predicts an image which usually is normalized output.



 mayool:

img without range [0-1] or img2 with range [0-1]?


Just note that when you are using transforms.Normalize, you are using z-score, so the output will not be in range [0, 1]. It depends on the mean and std but if you set mean and std = 0.5 for all channels it will be in [-1, 1], otherwise, out of this range.
You can find the proper input from the implementation of pretrained model, but usually, you will find normalization based on ImageNet values.