Uncle Frank, that helped enormously. I gave even commenting on the original picture because the contrast was so faint and the writing was completely illegible.
The first picture (on Uncle Frank's post) should be rotated 180 degrees, but it says the name of the person (presumably the owner) 飯沼 (Iinuma, a reasonably common surname).
Then it says (I think) 明星中 (Myōjō-chū) which normally I would think is the name of a Junior High School, i.e. Myōjō Junior High.
The K.I. are probably the owner's initials.