(keitai-l) Controlling the colour palette for an I-Mode phone

I'm using GoLive 5 with the i-mode plug in to create and manage some i-mode
web pages.
Where I'm having trouble is managing the colour palette so that images I put
on the site come out legible on an i-mode phone. I've seen some pretty sharp
pictures using 256 colour depth GIFs, but for some reason my GIFs come out
looking completely washed. Basically gradients don't happen for me.
Although this question is probably too general: Does anyone have any tips on
how to control the colour palette so I can see reasonable facsimiles on my
desktop and then be reasonably assured they'll look decent on the phone?

	Dave