Plugin accesses the caption shortcode via add_filter( \'img_caption_shortcode\', ... ).
By default, image authors are read out of the description of the respective image. Therefore, they have to be tagged in a specific way:
In the description of the respective image, accessible under ‘Media’ > ‘Edit’ > ‘Description’, the image author (or multiple image authors) have to be wrapped in <author></author> tags.
If there are no authors in image description, the plugin tries to read authors from the image’s Exif information. If successful, image authors are automatically saved into image description.