Using coins for scale is discouraged as it will require people unfamiliar with them to look up the dimensions or guess, both of which defeat the purpose of the object in the first place. Coins can also reinforce a geographical bias, and some coins' designs are copyrighted.
Ideally, a photograph should include a ruler with the subject (example) or an added scale marking.
SI ("metric") units are the most commonly used worldwide (see meter and centimeter).
Deutsch: Dieses Foto wurde von der Autorin und Fotografin des SalzburgwikiWald1siedel erstellt und unter nachfolgend aufgeführter Lizenz veröffentlicht. Das Bild kann frei verwendet werden, wenn ich als Urheber genannt und die weiteren Lizenzbestimmungen eingehalten werden.
English: This photograph was taken by the author and photographer of the austrian Salzburgwiki/Benutzer:Wald1siedel Wald1siedel and released under the license(s) stated below. You are free to use it for any purpose as long as you credit me as the author and follow the terms of the license.
Um mir ein Belegexemplar zu senden, kontaktiere mich auf meiner Diskussionsseite User talk:Wald1siedel / To send me a voucher copy, please contact me on my User talk:Wald1siedel
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.