You can only try to find the original - online with a search engine, if it's from a book with a database, some libraries have (online as well).
Is a lousy job, since you have to describe the pic the way it has been posted origianally and/or know, in what kind of book, magazine etc it might have been printed first.
This
photo, for instance, can be only tracked back to the publication where it was published before - since there are no other data, the date when taken nor the original source/photographer can be found.
Imagine, you see that without the threat around it ...