About this scene:
Well, it's all about Luke's mysterious poncho. There are a number of still shots where Luke is wearing this poncho, but in the finished film the poncho is nowhere to be seen. The poncho actually only appears in these scenes in the final version of the film: when our heroes enter Docking Bay 94 to start their fateful trip on the Milennium Falcon and Luke puts on this poncho (for some odd reason) just before they go through the doorway, when Leia wraps it around Luke to comfort him on their flight away from the Death Star after Ben has been killed, and after the arrival at the Rebel base when Luke is wearing it as he gets off the small transport in the hangar.
It seems likely that some of the other scenes may have actually been filmed as alternate versions with Luke wearing his poncho. In fact, a good explanation of the Docking Bay 94 scene with Luke wearing the poncho would be that it was the only version of that scene available or that it was the best one to use, and so Luke had to be shown inexplicably putting on the poncho as they reach the bay doorway, just before there is a cut to the inside of the bay--and then not wearing the poncho again once they're on board the Falcon. In any case, this is merely an interesting look at alternate or missing scenes of Luke and his beloved poncho.
These stills have shown up in numerous locations including trading cards and Lucasfilm magazines.
Luke with floppy hat, goggles, and poncho.
Luke, posing in his poncho next to a lone vaporator.
An alternate version of Luke's poncho grief upon seeing his home destroyed.
Luke has located Artoo (as well as his poncho), but is soon to face the Tusken Raiders.
Han and Luke (in poncho) check out the ships in the rebel hangar.
Behind The UnScenes
George Lucas talks to Mark Hamill and his poncho about the burning farm scene.