1. Copy the palette for the image using ResEdit
2. paste the palette for the image into 4th Dimension
3. Change the CLUT ID (color lookup table) to 0 so that it becomes the default
palette on application launch. This way
Unfortunately, this solution means that you are stuck with that palette until
changed in the application (for all files). To minimize this drawback, try
starting with the default system palette and change only some obscure, less
used colors in that palette to the ones you want and leave the other
standard colors alone.