[Rowan]

Ok, the mac version is complicated. The Carrara icon is a package, and we need to get inside. So, save your leaf to an outside location eg the Desktop or a folder for temp items. Make sure you know where though, as you'll need it. Now, go to the Carrara icon. Right click (ctrl + click for those with 1 button mice) on it and select 'Show Package Contents'. This should open up a window with Carrara as the header and one item, a folder called 'Contents'. Open this folder. For some reason, opening a package set the window view to folder icons, personally, I'd change it to list, as that allows you to see your path. Open the folder, and you should see 3 items, you want 'MacOS'. Open the file again, then open 'Data', and there's the plants folder. The actual leaf itself I think needs to go into the 'Leaves' folder, although I'm not sure. Best way is to hold 'alt' whilst dragging the leaf to the file. That way it only makes a copy, and the original stays where it was. Terminal savvy users can probably do all this in one command line. But I'll leave that to them.