Great website find! I had a great time scrolling through the years and the promo posters.
A lot of those movies were "Adults Only" and shown at Adults Only theaters. Consequently as a teenager I was only able to briefly view the promo pics outside of the theater. That was back in the 60's and 70's. VHS changed all of that and made those kinds of films more available. Now we have the internet which has given us a completely new paradigm.
You youngsters are very fortunate.