Attribution information, such as the author's name, e-mail, website, or signature, that was once visible in the image itself has been moved into the image metadata and/or image description page. This makes the image easier to reuse and more language-neutral, and makes the text easier to process and search for. Commons discourages placing visible author information in images.
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.
https://creativecommons.org/licenses/by/3.0CC BY 3.0 Creative Commons Attribution 3.0 truetrue
According to article 27 of the Copyright Act (en/de/fr/it), works installed at or on publicly accessible places or ground may be pictured, and such pictures may be offered for sale, sold, transmitted, or otherwise published. The image must not be three-dimensional and it must not be possible to use the picture for the same purpose as the original.
The works must be permanently installed, but for the purposes of the law, "permanent" means a fixed installation which may be temporary -- time limited -- but not "accidental", e.g. due to transport of the work.