WMF problem

I have a problem with Windows Metafile Format:
  My program uses metafile as a template for output over it. Then I write
resulting metafile on TImage. I use original Metafile width and height.
Under Win'95-Win'98 all works well, but under WinNT 4.0 resulting metafile
greate then original. What is wrong?
    I will wait for any opinions.