Today the digital camera is ubiquitous, but photos used to be taken by momentarily exposing something called "film" to light. Yes, film--the ode to photo-sensitive chemical reactions that produced all of the pictures made before 1990 or so. Those images were, and quite often still are, transferred to photo paper and pasted into coffee table albums. Sometimes they were processed into transparent 35mm slides and projected onto white screens for everyone's enjoyment (or boredom, depending).
But film isn't digital, and it degrades with time and exposure to the elements, albeit far more slowly than you might imagine. Fortunately for posterity's sake, it's easy to digitize and even restore some of the original luster of your film, using today's flatbed and film scanners, plus appropriate software.