I'm also wondering this. I don't hate the new look, but it isn't what I'm used to. I also have screenshotted previous trees before with the old theme to keep as simple images, but now if I do that with the new theme, it won't match the rest of my trees. It's a total aesthetic nightmare! This change didn't really have to be made in the first place. They should just add a very simple toggle, so we can choose between the old theme and the new theme.