Intended for posts from sites whose MD5 hashes do not match any of the various images (full size, large, medium, small, thumbnails, etc) linked to in the source.
The most common reason for the hashes to not match is that the one at the source was revised by the artist at some point after it was initially uploaded to Danbooru. Another reason is that the source was added or changed sometime after the original image was uploaded, where the source is not where the image originally came from.
Fixing the source
If another source for the image is found, follow these instructions.
1. With the same filesize and MD5 hash, then change the source field to the new source, and remove the md5_mismatch tag.
Note: A source is legitimate only if it's hosted by the original artist
2. With a different filesize and the image is inferior, then just ignore it and do not upload it.
3. With a different filesize and the image is superior, then upload it if you consider the image worthy, then parent the original to the upload and tag the original upload with the duplicate tag.
If the author revised the image, follow these instructions.
1. Compare the changes between the images from the source and the image uploaded. Things to keep in mind:
- Visible changes. For example, fixed proportions (post #2586730), better shading (post #2573687), changes in the background (post #2564081), and watermark removal (post #2564090). Revisions like these should always be uploaded to replace the older image. You may use an image diff tool if needed.
- Changes in resolution. If the resolution is smaller and there are no visible changes to the image, ignore the image at the source.
- Artifacting. An image at the source may have more artifacts after it has been revised by the artist (post #792863). This may be difficult to account for, given you need a image diff tool. See below.
- Metadata and/or file format. The EXIF metadata information may have changed if the image data is the exact same. The file format may have also changed, and in cases like these, always upload the better file format: png over jpg.
- If the revision is bad, it would be helpful to tag it bad revision along with other supplementary tags.
Image diff tools you may find useful:
- Image sample
- Pixiv sample
- Twitter sample
- Nicoseiga sample
- Tinami sample
- Tumblr sample
- Pawoo sample None yet observed
- Deviantart sample
- ArtStation sample
- Yandere sample
- Drawcrowd sample
- Bad ID