LCL, DbImage, fix loading streams without header

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@43781 4005530d-fff6-0310-9dd1-cebe43e6787f
LazReport, PictureView, fix loading streams without header

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@43782 4005530d-fff6-0310-9dd1-cebe43e6787f