I would put a foreign key from sponsor to the gallery table so that you at least know which sponsor the gallery belongs to....
also I don't know how you are going to use it but if it was me and the sites from the sponsors were relevant I would maybe make two tables for that
programs - id int 11, name varchar(250), login_url varchar(250), ref_url varchar(250), desc text.
sites - id int(11), program_id int(11), name varchar(250), url varchar(250).
and then on your gallery table I would add a column called site_id int (11).
Maybe you want some relations to the model as well from your gallery and that is done the same way with adding a model_id field with the id of the model from the models table
Good Luck
you are on the right track mr