Update img2img.mdx

Author: patrickvonplaten

docs/source/using-diffusers/img2img.mdx

@@ -15,6 +15,7 @@ specific language governing permissions and limitations under the License.
 The [`StableDiffusionImg2ImgPipeline`] lets you pass a text prompt and an initial image to condition the generation of new images.
 
 ```python
+import torch
 import requests
 from PIL import Image
 from io import BytesIO