How does the pixel-perfect duplicate tag works

Posted under General

A question in tagging this since I hadn't much understand this tag well.

How this tag to be use anyway? Is it by quality or the file size? Since I notice some get the tag, but others don't despite the similar resolutions.

blindVigil said:

It means the images are completely identical down to every single pixel. The tag is added automatically by NNT's bot.

It also automatically removes the tag if added to a post that isn't a pixel-perfect dupe.