Custom Diffusion includes training the target images with a small set of real images to prevent overfitting. As you can imagine, this can be easy to do when you're only training on a few images! Download 200 real images with `clip_retrieval`. The `class_prompt` should be the same category as the target images. These images are stored in `class_data_dir`.  
```bash
python retrieve.py --class_prompt cat --class_data_dir real_reg/samples_cat --num_class_images 200
```