An idea hit me. I pulled out one of the negatives, placed it on a white sheet of paper, took a picture of it with my camera, then uploaded the image to my computer. This is what it looked like after I cropped away the white paper:
Next, using the "invert" filter in PhotoShop Elements, I changed the negative image to this very light positive one:
I then tinkered with the lighting adjustments (highlights/shadows and brightness/contrast) to make the picture as clear as I could and realized it's one I've never seen before. The final result still isn't great, but I recognize both the little girl and the outfit she's wearing from another old photo, a formal studio portrait. Here, after all the tweaking I know how to do, is an approximately 68-year-old snapshot of me, picking my nose.
The song is "Picture," by Kid Rock and Sheryl Crow.
Thanks to alexiahazlett for posting the song and its lyrics on YouTube.