util.open_and_resize_image should not be hard code

[ttpro1995]

In script NeuralSytleTransfer/train.py

the open_and_resize function should not hard-code

styleImg = transform(util.open_and_resize_image(opt.style_image,256))
contentImg = transform(util.open_and_resize_image(opt.content_image,256))

rather, it should use parameters from opt.imageSize