English: Flickr's dropdown license chooser as seen on a file page from the point of view of the uploader. Licenses acceptable on Wikimedia Commons are Public Domain Dedication (CC0), Attribution, and Attribution-ShareAlike. Note the confusing similarity between "Public Domain Work" and "Public Domain Dedication (CC0)". The former, actually the Creative Commons Public Domain Mark, is not a valid legal instrument and is intended to denote works already in the public domain. Files marked with this on Flickr can be uploaded to Commons only if the reason for the file being public domain is made clear, such as by adding a public domain tag like {{PD-old-auto-expired}} or {{PD-USGov}} (see COM:PDM and Commons:Requests for comment/Flickr and PD images for more information). Users who want to dedicate their own works to the public domain should use CC0 instead. More information on the different license tags on Flickr can be found here.