I got rid of the single dimensions using;
img = torch.squeeze(img)
This gives image shape = torch.Size([480, 640])
I get an error message:
TypeError: Invalid shape (6, 480, 640) for image data
EDIT - I now realise that the maximum number of images that can be shown is 4, so by sending 4 images I get a shape of (480, 640, 4) and now I have a new problem; it only shows 1 image.