[UPHPU] best method for css rounded gradient boxes

[miles]

I like to use Inkscape(SVG) to mock up my output pages (beats the 
drawing on paper thing and Firefox & Safari users can display it in the 
browser for full effect).  I've drawn some nice looking gradient boxes 
(with rounded corners).  Now I have to add it to my program so I'm 
assuming I'll add it to the css.

What is the best way to duplicate a gradient rounded box in css ?  a) 
fill the entire div with a png image with no-repeat ?  b) slice the 
image and go the 4 corners route with transparent pngs ? 

the entire image seems the easiest but I'm wondering about performance 
of downloading large images especially when there are several / page. 

any suggestions ?