No, because I already did. You might want to actually know what you're talking about before you try and say these kinds of backhanded compliments. For instance, are you next going to tell me that they couldn't have used gray in the portraits, either? Oh wait, they did:
[link]I can't help it if you fail to see the congruent colors that make it match the other fire lord portraits. Their portraits are NOT monochromatic, and you might be thinking of the scene where it's being illuminated with only lanterns, which is going to effect the way the color plays on the screen (and is almost all of the screenshots). That aside, you can actually see that the left most portrait has green leaves in it, and that Azulon is standing on a turtle that has green on it.
[link] If you can't see it's green, take a color theory class.