File talk:Appearance of the shutter at various speeds.gif

Hi charlie, thanks for the animation file. I what to use it in an workshop about photography basics.

You have a permission/license conflict. You mentioned "public domain" AND a "creative commons". Public domain means everyone can use without any condition (even not attribute you as author of the image). The Creative Commons is more restricted (a user has to share alike and attribute the author).

Please decide with one of the two licenses you want to use.