Is it Safe to Use? – Guidelines for re-using images from Wiki sites — Naomi Korn Associates

"When searching for images for commercial use we often turn to Wiki sites as first port of call, but are all the images safe to use for commercial purposes?  Not everything posted in the Commons or Media sites or used on a Wiki page is in fact open access. Some images (particularly in WikiPedia), are there with an explanation that they are used on the site because they are all over the web and nothing else could be found or the licence holder could not be found.  Not everything that says it is “Public Domain” or “Creative Commons 0” actually is, depending on where you live.

It is easy to scroll down to the rights section below the image, and open the blue “More Info” button to check what kind of licence the image carries. There are various types of “CC” licence and the letters after CC tell you whether any restrictions apply. Importantly, you may not be allowed to change the photo (eg crop it or incorporate it into another work (ND) or you may not be allowed to use it commercially (NC). Explanations for the various letter codes can be found here https://creativecommons.org/licenses/.

The issues I will consider fall roughly into two categories: works of art and contemporary photographs of landscapes and architecture. ..."