Thank you for the compliment.
The short answer is “No”. While the school [publication] does in fact meet one of the two requirements for a work to be considered work-for-hire:
(1) A work specially ordered or commissioned for use as a contribution to a collective work (such as a newspaper, magazine, anthology, or encyclopedia.
In order for the paper to claim work-for-hire, you must also have signed an agreement stating that the work was work-for-hire (work made for hire).
If no document exists with your signature scrawled on it ... The school has no claim to your photographs.
However, these silly requirements have not stopped entities from claiming everything from work-for-hire to copyright privileges. The school could also render your argument moot by claiming that because you were a student you were technically an employee of the paper.
I suspect from your follow-up question that the school or someone else is now reselling your photos for profit? You are dealing with a copyright issue. And due to the fact that the works in question were created a quarter of a century ago, no one, not even yourself, can be certain of the specifics of the original working agreement.
The paper may well believe they own the work and have every right to do with it as they please. The 3rd party may believe the work is in the public domain*. Regardless, the school paper should have come to you with a request for permission to resell or reuse the work - assuming they kept records identifying you as the original author.
My advice is this: Get professional help from a lawyer who specializes in intellectual property if this is important to you. There are too many variables at play with this scenario for you to handle without the assistance of someone who knows their way around the law. You can certainly try sending the 3rd party a cease and desist letter, but I would suggest looking into your local Lawyers for the Arts chapter for qualified legal advice.
*Public domain - Copyright term for unpublished / unregistered works: Life of the author + 70 years.