There's an article in a paranormal site tried to get some answers about a question: why ghosts seen wearing clothes? If ghosts per se are spirits or just energies of dead people, why most if not all ghosts apparitions were seen wearing their clothes or form of clothings. My personal opinion about this is "it's their consciousness creates their own shape or image if seen by clairvoyant people especially those earthbound souls". The soul has it's own consciousness to create a reality based on what it's mind dictates or accepts to a particular event. Seeing ghosts with clothes are not different with seeing ghosts with ugly faces such as blood or misformed because that's a reality what the ghost accepts. If a person could awaken a ghost or the soul itself realized his fate in the physical realm, they could change their image to a better manifestation when seen by clairvoyant people.
Just want to share the article with regards to this topic: http://paranormal.about.com/od/ghosthuntinggeninfo/a/aa042708.htm