It is possible to bypass category selection by using the plugin's own syntax. You can disable the plugin in all categories by selecting None.

The following syntax will trigger the creation of the image in individual articles:

imagefromarticle, inside { }.

Note Use only one plugin syntax per article. Any extra occurrence of the syntax will be ignored (but cleanly removed).

Warning You can end up with duplicate images if an article contains the plugin syntax AND is selected through the category selection mechanism.