Research is important. A telephone call to the publication in question will probably help. The receptionist or whoever answerers the phone can be a great source of information. They know the organisation and are best suited to get you to the right person.
This is the point you find out if they are interested or not. If not be polite and ask them for the reason why not. It may be they already have a photograph, or it's not the sort of thing they are interested in. Don't take rejection as a negative, take the opertunity to find out what they want. You may be able to supply other pictures. Have a pen and paper handy and make notes especially of who you speak too. ( Helpful if you need to contact them again)
If they do want you picture, now is the time to ask about fee's, repeat usage, copyright etc. Don't be afraid to ask. If they are sourcing pictures externally they expect these sort of questions. They may even have a printed document they can send you.
Good luck
John C