The phrase "identifiable person" refers to someone who can be recognized or distinguished easily. It means that their identity, such as their name, appearance, or other characteristics, can be determined with relative certainty. Full definition
They may need copyright permission from the owners of any identifiable works of art included and may need model releases from identifiable people included. (law.stackexchange.com)
In my experience, effective blogs have real identifiable people as authors. (lawyerist.com)
Even in the U.S., permission is required in order to use photographs of identifiable people in many contexts (there are exceptions, but «on my author website where I also promote my books» is generally not among them). (rmfw.org)