Need help...

[Nai]

Okay, We are using Level Generator for Londa. (Yes, I know, the level generator). But, well, The left side of the map should be all Water except for that island. Anyway, I open up levelgen.png or whatever the default map is and I open up my image for the level gen map. I convert my map to 16 Million colors and then I copy the blue from the defualt map and then click on my map and I fill in the left side of it blue. Now, when I convert it back to 256 Colors it changes the Blue color from 0,0,255 to 0,0,198. Then it doesn't make the water. So, um, help?