In Stanford CS 231N course assignment 3 (http://cs231n.github.io/assignments2017/assignment3/ 20) you are invited to implement Gatys et al.'s style transfer algorithm (https://arxiv.org/abs/1508.06576 6). Doing it in PyTorch is one of the possibilities (the other one is TensorFlow) and they provide an ipython notebook with some initial code and correctness checking routines. You may find it helpful.