Custom Stationery: HTM Question

I am trying to creat custom stationery for Outlook 2007.

I have a jpg file I have opened up in Word 2007 and saved as an HTML
document and put it in the Microsoft Office/Stationery/1033 folder and it
does show up in the Outlook stationery picker.

But...when I use it as stationery it does not behave like other HTM
stationery; that is it does not expand with the message window when this
window is increased in size.

Any help will be appreciated.

If I haven't made myself clear let me know and I'll try and be clearer.

Thanks,
BobB