[vtkusers] set scalars into vtkImageData

[flin at enders.tch.harvard.edu]

Dear all,

If the size of scalars(e.g. vtkUnsignedCharArray) does not match the
dimensions of vtkImageData, what will be contained in the tmpImgData after
the following:

tmpImgData->GetPointData()->SetScalars(newscalars);

Many thanks.

/faith