A post that doesn't exactly match the post at the source.
A post can be a MD5 mismatch for several possible reasons:
The file was modified by the uploader, for example, by editing it or resaving it. Uploaders shouldn't modify files.
The file was revised by the artist. The revised version may be uploaded as a new post.
The file is an image sample. Ask for the file to be replaced with the full version in topic #16765.
The file was modified by the source site, for example, by recompressing it to a lower quality. Nothing can be done here.
The source is not where the file originally came from. The uploader got the file from a different source. The source should be changed to point to the original source.
An MD5 hash is a signature used to tell if two files are the same. Two files with the same MD5 hash are exactly the same. Two files with different MD5 hashes are different files, even if they look the same. They may have differences that can't be seen by the naked eye, such as different image compression or quality levels, or different image metadata.
