Summary (Style Sheets and PNG)
Biggest single bandwidth gains may be deployment of style sheets
15 of 40 images in our sample were easy to convert to CSS
An additional four images are if the font is available
3 images if negative margins are allowed
3 images can be replaced by a mixture of CSS and images
Style sheets gain two ways:
The representation is smaller than image formats
and by reducing the number of protocol requests
PNG saved bandwidth
But not very much, in our tests
For big images, PNG has significant size savings over GIF
there are other good reasons to adopt PNG - e.g. no patent problems and gamma correction
Jim Gettys