my tips above will probably work on image ready too
but I don't have it, so you'll have to translate :)
edit: showing off:

(
but the hedgehog can never be buggered at all foreskin of the apocalypse,
Fri 25 Jan 2008, 22:55,
archived)
image ready has a small arrow that one can click
and choose 'optimise to filesize'.
This, as might be expected, optimises to a filesize.
(
LordManley twitter.com/LordManley,
Fri 25 Jan 2008, 22:58,
archived)