The Shawshank Redemption

The Shawshank Redemption Loophole: How did Andy stick the poster back from the tunnel at the time of escape?
Let's imagine how Andy was escaping. First he removed the poster of Raquel to enter into tunnel,assuming the best case, he just removed it from bottom two corners. Now he entered into the tunnel.. Now how could he stick the poster from inside of the tunnel. Apart from this, at the other side of the tunnel, he came out with head first so definitely he would have entered with head first.And tunnel wasn't big enough so that he could flip his position inside it. In that case there is no chance that he could stick that poster as neatly as shown in the movie.
-Quora