DOCBOOK: Graphics across multiple formats

["John R. Hall" <overcode@lokigames.com>]

I'm in the process of creating a large technical document, and I would
like to embed bitmapped graphics. I need the graphics to work with the
DVI and HTML backends with no changes to the source document, and I
would like to avoid the .GIF format if possible. I'm using the free
toolchain (Jade etc), DocBook 3.1, and whichever stylesheet is the
default (cygnus-both.dsl, I believe). How can this be done?

Also, is there a way to specify that table columns should not have equal
widths? I'd like to assign a 30% weigth to the first column and a 70%
weight to the second.

Thanks!
John