Does This Repeated Background Image Need To Be 10 Pixels Tall?

[abajan]

I’ve been searching for a site that could be used as a template or guide upon which to base a centered fixed width layout, with drop shadows on both sides of the content area.

Six Revisions’ design was just what I was looking for but what could be their reason(s) for using this repeated background graphic measuring 980px × 10px for the shadows when IMO a 1px tall one of similar width would have sufficed? Would not such an image have enabled faster page loading, even if just slightly, since it would have had a smaller file size? (Incidentally, a PNG image would also have had a smaller file size but I realize some older browsers don’t recognize that format.)

Just curious.