you are a little vague though I make out that you are having problems rescaling. Simply make the door bigger or smaller in all dimensions at once by grabbing the middle of the scale tool, alternatively you can grab the others to change the scale on the x,y or z.

Also if you look in the channels box, highlight scale, then go over your image and keep clicked the middle mouse buttonm and scrub left and right to change the size attribute. Hope this helps.