Update tutorials/metadata.md

Give specific examples of how to download things

tutorials/metadata.md

@@ -1,4 +1,13 @@
 # Working with the Metadata
+
+## Downloading all the metadata files at once
+
+Install the huggingface-cli utility (via pip). You may then use the following command:
+
+    huggingface-cli download Spawning/PD12M --repo-type dataset --local-dir metadata --include "metadata/*"
+
+## metadata format
+
 The metadata files are in parquet format, and contain the following attributes:
 - `id`: A unique identifier for the image.
 - `url`: The URL of the image.
@@ -24,3 +33,14 @@ Once you have opened a maetadata file with pandas, you can get the URLs of the i
 urls = df['url']
 ```
 
+### Download all files mentioned in metadata
+
+If you want to just grab all files referenced by a metadata collection, you may try this (adjust to taste):
+
+    img2dataset --url_list $file --input_format "parquet" \
+    --url_col "url" --caption_col "caption" --output_format files \
+    --output_folder $dir --processes_count 16 --thread_count 64 \
+    --skip_reencode true --min_image_sizel 654 --max_aspect_ratio=1.77
+
+
+