Fix pytorch image classification example
Updates the `examples/pytorch/image-classification/run_image_classification.py` script to use the new Image feature to pass the failing [CI test](https://app.circleci.com/pipelines/github/huggingface/transformers/31642/workflows/b1aa40eb-2edc-4b54-963b-f11058072a7e/jobs/327951/artifacts) (I've also updated the `hf-internal-testing/cats_vs_dogs_sample` dataset on the Hub for that).