Some of the content on this site is licensed under the GNU Free Documentation License. From Wikipedia:
The GNU Free Documentation License (GNU FDL or simply GFDL) is a copyleft license for free content, designed by the Free Software Foundation (FSF) for the GNU project. It is the counterpart to the GNU GPL that gives readers the same rights to copy, redistribute and modify a work and requires all copies and derivatives to be available under the same license. Copies may also be sold commercially, but if produced in larger quantities (greater than 100) then the original document or source code must be made available to the work's recipient.
You can copy and reuse these photos if you properly indicate the author's name and the License itself. A link to the author's Gallery page should be visible with every published copy of the pictures.
You can read the full text of the License at http://www.gnu.org/copyleft/fdl.html or download our local copy gfdl.txt.