When a motion picture is released, there is usually one official poster.  Blockbuster films may have three or more different ones: teaser posters; theatre posters, bus stop posters, etc.  But in almost every case, the studio prepares a variety of potential poster designs.  These are then narrowed down to the "official" choices.  The rejected designs rarely see the light of day.

In the case of Bigger Than The Sky, at least 23 designs were prepared before the official poster (left) was chosen.