A post that is the same or inferior to an already existing post. This tag only applies to inferior posts that were uploaded [b]after[/b] an already existing identical post.

Duplicates should not be confused for the following:

* [[image sample]], an image typically used by sites to load images faster.
* [[md5 mismatch]], an post that has a different md5 from the file at the source.
* [[revision]], a post that has been revised by the artist from a previous version.
* [[variant set]], posts with a similar base, but non-trivial differences.
* [[scan]], a post that has been scanned from another source.

A few cases where the tag applies:

* Images with [[pixel-perfect duplicate|identical pixel data]], but different metadata.
* Lower resolution versions of the same post.
* [[Resized]] posts. Note that duplicate resized posts should not be tagged with [[md5 mismatch]].
* Images of generally lower quality; often a result of [[jpeg artifacts]].

Before you upload something, check if it has already been uploaded by using the "IQDB image search":http://danbooru.iqdb.org/ or the "Find similar" button.

Most duplicates are tagged manually; only [[pixel-perfect duplicate]]s are tagged automatically. There is no automated system in place to accurately tag non pixel-perfect duplicates given how easy it is to confuse them for the above (with the exception [[image sample]]s where the original is already uploaded).

h6. Notes:
* [b]Do not flag a duplicate post for deletion if your only reason is that the post is a duplicate.[/b]
* Don't add the duplicate tag on posts with visual differences ([[variant_set|variants]], [[revision|revisions]], [[textless version]]s etc.).
* Avoid uploading visually identical posts.
** Check for differences with "DuplicateBooru":https://duplicatebooru.zipfiled.info/ if you are unable to confirm with your own eyes.

h4. Related tags

Not to be confused with [[multiple sources]], although they may overlap sometimes.

* [[multiple sources]] is about outside sources -- it means that multiple copies are available outside Danbooru.
* [[duplicate]] is about Danbooru -- it means that we have multiple copies of the same image.

h4. See also

* [[help:upload]]
* [[help:image source]]

h4. External Links

* "How can I tell exactly what changed between two images?":[https://photo.stackexchange.com/a/11739]
* "Diffchecker":https://www.diffchecker.com/image-diff [tn]Online compare images[/tn]
* "ImageMagick":https://www.imagemagick.org/ [tn]Multitool with "compare":https://imagemagick.org/script/compare.php function[/tn]
* "XnView MP":https://www.xnview.com/en/xnviewmp [tn]Image viewer. Support EXIF, IPTC, XMP metadata[/tn]
* "ExifTool":https://exiftool.org/ [tn]Command-line application for work with metadata[/tn]
duplicate