When you share your work on Wikimedia Commons with a free license, you grant anyone permission to use, copy, modify, and sell it (as long as they follow the rules of the license).
What is allowed on Commons
You may upload works that you created entirely yourself. This includes photos and videos of:
natural landscapes, animals, plants
public figures and people photographed in public places (only with consent in some cases, depending on local laws)
useful or non-artistic objects
You may also upload original graphs, maps, diagrams, and audio.
What is not allowed on Commons
Commons can’t accept work created by or based on the work of others – including photographs of it. By default, you can’t upload someone else’s work. This includes material such as:
screenshots of TV shows, movies, DVDs, and software
drawings of characters from comics, TV, or movies – even if you drew them
most pictures published on the internet
photos of you not taken by you (the copyright holder is the person who took the photograph unless it is a formal work for hire)
However, there are some exceptions
You can upload someone else’s work if the author granted permission for anyone to use, copy, modify, and sell it – by releasing it under a free license. (Be sure to provide a link to the source, where the license is stated.)
You can upload someone else’s work if it is in the public domain (usually very old works).
You can upload your photographs of public domain works, such as old buildings, statues, and art.