in the oft-mentioned'Optimise' window panel
there's an option marked 'dither' and a percentage slider/textbox...
(
JustHere4Coffee remembers when all o' this were car parks,
Sun 15 Jun 2003, 21:01,
archived)
Why
Thankyou very mooch sir!
(
HappyBadger,
Sun 15 Jun 2003, 21:03,
archived)