The reason why I post this duplicated image is because the source URL and MD5 are different from parent post. I'm doing MD5 search through danbooru API to fetch metadata, and even though the parent image and the one I have are pixel identical, they have different hash. I thought it would better to just append the alt source and MD5 to the parent post and delete this one.

I'd better using IQDB to do pHash search instead of MD5.