The image I showed the other day of the brass door with handle and pink surrounding corrosion raises an interesting point. The apparent subject, some old piece of equipment is really quite uninteresting and were someone to title the image "furnace door with corrosion", you'd really have little reason to want to look at it.
What I think the image is about is PINK. To me that is the subject. The colour is so unexpected and attractive against the bronzy background that the colour becomes the primary subject and where the colour came from is secondary at most.
The interseting question will be whether if you start thinking of it as a "pink" instead of as a door, will it change the way you think about the image.