I earlier sent an e-mail and PM on Flickr to the photographer to release the picture under the CC-BY-SA license and he agreed (the picture was previously listed as "All Rights Reserved" prior to this).
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.