...it now compiles, but there are a boatload of warnings of the type:
1>opencv_core246d.lib(alloc.obj) : warning LNK4099: PDB 'opencv_core246d.pdb' was not found with 'opencv_core246d.lib(alloc.obj)' or at 'c:\users\trevor\documents\visual studio 2012\Projects\vipsSample\Debug\opencv_core246d.pdb'; linking object as if no debug info
1>opencv_core246d.lib(arithm.obj) : warning LNK4099: PDB 'opencv_core246d.pdb' was not found with 'opencv_core246d.lib(arithm.obj)' or at 'c:\users\trevor\documents\visual studio 2012\Projects\vipsSample\Debug\opencv_core246d.pdb'; linking object as if no debug info
1>opencv_core246d.lib(array.obj) : warning LNK4099: PDB 'opencv_core246d.pdb' was not found with 'opencv_core246d.lib(array.obj)' or at 'c:\users\trevor\documents\visual studio 2012\Projects\vipsSample\Debug\opencv_core246d.pdb'; linking object as if no debug info
The sample program does run now though.