Fix for reusing memory in image class.

git-svn-id: http://svn.boost.org/svn/boost/trunk@84049 b8fc166d-592f-0410-95f2-cb63ce0dd405
fixed a merging issue.

git-svn-id: http://svn.boost.org/svn/boost/trunk@84050 b8fc166d-592f-0410-95f2-cb63ce0dd405