Thanks Jezebel for your replies.

I do have a fair bit of experience with rasterized graphics (and
Photoshop), but vector graphics are totally new to me.

I need vector graphics in my Word document because I have to include
this rather intricate layout in my report. My final product will be a
PDF produced from this Word doc.

BTW, I found out that .wmf format works quite well for vector in Word.
However, my images always come out in the wrong orientation (I use
PStoEdit with Ghostview to convert the PDF to .wmf). Is there any way
to rotate it?