I had ask one of my friend who live in Canada,
She suggest me to use "Adobe ImageReady" in this 
case. (the programme is included in photoshop 
already, you can find in in Photoshop's folder)

I had try it and it's really cool (well, to me).
It reduce half the file size, and the images is 
good. You can have a look :
http://cyan.rubberslug.com/gallery/master_query.as
p?SeriesID=2779&Gallery=cyan

That trowa+Quatre+Lion sequence only take 205k 
now, and the image is far better then the past 
one.

For the sequrence of Quatre and the 3 men, the 
file size down to 452k, and the clolor balance 
image is very very good here!! Look at the eye 
color of Quatre!!!!!