By the way, the official description is

Piece of thermal insulation tile floats near the Shuttle Columbia

A small piece of thermal insulation tile floats in space near the Shuttle Columbia. The cloudy surface of the earth is used as a background.

http://images.jsc.nasa.gov/luceneweb/caption.jsp?searchpage=true&to_day=31&from_year=1981&from_month=8&to_year=1996&datesearch=Go&hitsperpage=100&from_day=1&to_month=12&pageno=21&photoId=STS61C-31-002

But since when NASA can be trusted  :P

Judging from the film strip info below it doesn't look as this was put together from several images. But then the left and bottom sides of the triangle seem too perfectly aligned, don't they?

http://www.giveawayoftheday.com/