Legal Question in Civil Litigation in Massachusetts

If a Photographer finds their photos used without permission

I assume, and correct me if I am wrong, that these photos are not registered or otherwise tagged as being yours.

In general, unless you allow or permit property to be displayed or there is an exception to the rule, they are still yours.

I would suggest that you contact the site's "owner" or webmaster, and advise them that they are yours, and demand they they remove them subject to legal action.

See what happens, and re-post or contact me.