[docs] Fix image in SDXL docs (#4267)

fix image link

Author: stevhliu

docs/source/en/api/pipelines/stable_diffusion/stable_diffusion_xl.mdx

@@ -206,7 +206,7 @@ Let's have a look at the images
 
 | Original Image | Ensemble of Denoisers Experts |
 |---|---|
-| ![lion_base_timesteps](https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/lion_base_timesteps.png) | ![lion_refined_timesteps](https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/lion_refined_timesteps.png)
+| ![lion_base_timesteps](https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/lion_base.png) | ![lion_refined_timesteps](https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/lion_refined.png)
 
 If we would have just run the base model on the same 40 steps, the image would have been arguably less detailed (e.g. the lion eyes and nose):