You clone a plant and you add the image(i.e plantDaisyWhite_com) you want to change to your package. You also have to get the matching SPT2 resource from the FullBuild0(isn't included with the clone) and add it to your package, you'll need that for the thumbnail(it won't show without it). Then you give the SPT2 the same instance number as the _SPT, and open it in Grid and change the instance number in the RCOL block to the same. Then you open the _SPT in a hex editor, look for the name of the image(i.e. plantDaisyWhite_composite_d.tga) and change it while keep the same amount of characters(i.e. plantDaisyPurpl_composite_d.tga).

There's two listings of the name so you have to find and change both. Then you make a hash of the name without the .tga(i.e. plantDaisyWhite_composite_d) and change the instance number of your image to the number you hashed.