I would like to add a new type of deravative file, in addition to “Fullsize”, “Thumbnail” and “Square Thumbnail”. For this it seems to me that I must add a new Strategy in application/libraries/Omeka/File/Derivative/Strategy. But how to create this new strategy without directly adding a new file in this folder ? I can not add a Strategy from a plugin that I can enable/disable ?
What I would like to do is allow the admin, from admin theme, to choose if he wants this new type of derivative file or not. How can I do that ?