Help with a Png's Pallete

[wowwow]

Hi , i have done a map but it has 256 entries in the pallete. There are lots of colors that i dont need so i want to just use 132 colors or less , but i dont know how to delete this colors. I have TweakPng but i can only delete colors that are in last poitions , i would like to be able to move colors for put them at the start (first entries) and put the bad colors at the end for delete them.
How can I? I have counted and i think that my map justhave 60 or 70 important colors.

[CyberShadow]

You'll need to use a more capable image editor:

http://worms2d.info/Colour_map#Authoring_instructions

[Metacooler]

I recommend Gimp. You can halve the number of colours without being able to tell the difference, in most cases.