update readme

README.md

@@ -9,7 +9,10 @@ language:
 
 **Homepage:** http://vawdataset.com/
 
-**Repository:** https://github.com/adobe-research/vaw_dataset; Note: The raw dataset files will be downloaded from: https://github.com/adobe-research/vaw_dataset/tree/main/data, where one can also find additional metadata files such as attribute types. The train split loaded from this hf dataset is a concatenation of the train_part1.json and train_part2.json.
+**Repository:** https://github.com/adobe-research/vaw_dataset;
+- The raw dataset files will be downloaded from: https://github.com/adobe-research/vaw_dataset/tree/main/data, where one can also find additional metadata files such as attribute types. 
+- The train split loaded from this hf dataset is a concatenation of the train_part1.json and train_part2.json. 
+- The image_id field corresponds to respective image ids in the v1.4 Visual Genome dataset.
 
 **LICENSE:** https://github.com/adobe-research/vaw_dataset/blob/main/LICENSE.md