Not totally true. Please no need to ask how I know.
Not to mention our high school yearbooks have been digitized and are all on-line.Not totally true. Please no need to ask how I know.
Check out the 8mm, 16mm, and later VCR movie cameras, the slide carousel projectors, the 110, 126, and 35mm camera undeveloped films.
But most of the really juicy embarrassing photos are kept in easily accessible photo albums which were used by parents and grandparents to show your prospective girlfriend/boyfriend, new wife/husband, best friends, classmates, children, grandchildren, and seldom seen relatives.