The answer to all of your questions is Yes.
You can define a value list of the people in your photos and use that value list to format a field with check boxes so that you can select people as shown in a given photo.
You can use that field to find photos of a person in a find, but as in FileMaker 5, be careful of searching for someone who may have a similar name such as searching For Fred and getting Fredrick Jr.
And you might find it useful to set up a table of people--your "master list" and linking it to your table of photos with a join table so that a photo record can link to many people and a people record can link to many photos.
Photos::__pkPhotoID = Photo_People::_fkPhotoID
People::__pkPeopleID = Photo_People::_fkPeopleID
For an explanation of the notation that I am using, see the first post of: Common Forum Relationship and Field Notations Explained
Thanks so much for your quick reply.
The operative phrase was checkbox. Thanks also for the tip re the table of people. I'll certainly do that.