thanks everyone. To get to the point:

It is 256 colours
It is 320 x 3200
It is not masked yet.

Some things that can be the cause:
-It's only grey and white
-Lot's of JazzBlue
-Not all the pallet-layers are used in the set

I can't come up with more.
I'll post the full-size BMP image tommorow so you can "examinate" it.
I'd like to upload it myself if you don't mind. (and of course you'll be credited )


EDIT:
I found it. It seems the Automask didn't work. No I finished the official mask it works perfectly!

So if everything goes right, I'll be able to upload the set next week with an examplelevel.
Thanks Everyone