And all of those pretty images are being defined by two simple vector shapes like these:
NOTE: In order to retain your vector shapes don't merge the layers, and when saving, save your original document in the native Photoshop format (.PSD) To make copies of the image suitable for the web or email, whatever, then use Photoshop's "Save for web" feature to save a copy of the image as a .JPG, .GIF, or .PNG. But always keep your original document in .PSD format otherwise you'll lose all your vector data and your layers will get flattened to a single image.