[training] Convert to ImageFolder script

Author: hlky

examples/dreambooth/README.md

@@ -742,3 +742,29 @@ accelerate launch train_dreambooth.py \
 ## Stable Diffusion XL
 
 We support fine-tuning of the UNet shipped in [Stable Diffusion XL](https://huggingface.co/papers/2307.01952) with DreamBooth and LoRA via the `train_dreambooth_lora_sdxl.py` script. Please refer to the docs [here](./README_sdxl.md).
+
+## Dataset
+
+We support 🤗 [Datasets](https://huggingface.co/docs/datasets/index), you can find a dataset on the [Hugging Face Hub](https://huggingface.co/datasets) or use your own.
+
+The quickest way to get started with your custom dataset is 🤗 Datasets' [`ImageFolder`](https://huggingface.co/docs/datasets/image_dataset#imagefolder).
+
+We need to create a file `metadata.jsonl` in the directory with our images:
+
+```
+{"file_name": "01.jpg", "prompt": "prompt 01"}
+{"file_name": "02.jpg", "prompt": "prompt 02"}
+```
+
+If we have a directory with image-text pairs e.g. `01.jpg` and `01.txt` then `convert_to_imagefolder.py` can create `metadata.jsonl`.
+
+```sh
+python convert_to_imagefolder.py --path my_dataset/
+```
+
+We use `--dataset_name` and `--caption_column` with training scripts.
+
+```
+--dataset_name=my_dataset/
+--caption_column=prompt
+```

examples/dreambooth/convert_to_imagefolder.py

@@ -0,0 +1,37 @@
+import argparse
+import json
+import pathlib
+
+parser = argparse.ArgumentParser()
+parser.add_argument(
+    "--path",
+    type=str,
+    required=True,
+    help="Path to folder with image-text pairs.",
+)
+parser.add_argument(
+    "--caption_column", type=str, default="prompt", help="Name of caption column."
+)
+args = parser.parse_args()
+
+path = pathlib.Path(args.path)
+if not path.exists():
+    raise RuntimeError(f"`--path` '{args.path}' does not exist.")
+
+all_files = list(path.glob("*"))
+captions = list(path.glob("*.txt"))
+images = set(all_files) - set(captions)
+images = {image.stem: image for image in images}
+caption_image = {
+    caption: images.get(caption.stem)
+    for caption in captions
+    if images.get(caption.stem)
+}
+
+metadata = path.joinpath("metadata.jsonl")
+
+with metadata.open("w", encoding="utf-8") as f:
+    for caption, image in caption_image.items():
+        caption_text = caption.read_text(encoding="utf-8")
+        json.dump({"file_name": image.name, args.caption_column: caption_text}, f)
+        f.write("\n")