Yes, CNNs learn best with pixel values / 255
Furthermore you also probably should normalize by channel so that your values distribution is centered around 0 and standard deviation is 1.
Here is a script 231 to do that for PyTorch.
Note: for pretrained network on ImageNet you should use ImageNet mean and stddev:
transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])