Def tool but I always use indexed images, so it does not change it then.
Applying a new palette to an image: it is only when I convert it to indexed from RGB that it asks me which palette to use.

So, the process would be:

1) Extract bmp from all units angles
2) Open Image ready and delete main palette, creating a new one with the first screen, then add to the fresh created palette the palettes from the other angles
3) Convert the creature images to indexed colors and apply the new palette when doing this

This is right?

Another matter: the creatures I extracted come with 255 colors. Is it a way to reduce them to 155 or so? I am asking this because your creatures have about 155, and it seems 255 is looking weird/too many

Another annoying thing is that I don't know where that damnt main palette is. I created a new layer and pasted inside all creatures frames from all angles. Then I added them to the main palette and saved it both as main palette and on the desktop as ACT file.

Now when I am asked which palette I want it shows this:


So, which is the main palette among those...I choose "another" then I selected the ACT file on the desktop.