Appearance:
You can change the background image and the logo of the login window.
Background: You can use the Select button to choose a replacement image for the background of the login window. By default, the application directs you to the folder containing the Desktop Pictures of OS X (/Library/Desktop Pictures/...). It is preferred to load an image the same as your screen size or a 256 x 256 PNG image (512 x 512 for a Retina screen) like the original one.
Formats accepted: BMP, GIF, JPEG, JPEG 2000, PNG, PSD, TGA, and TIFF.
You can use the Restore option to put the original background image in the login window.
Logo: You can use the Select button to choose a replacement logo for the login window. You must use an image of the same size (79 x 95 pixels by default, 160 x 190 for a Retina screen) or size proportional to the original image. The application directs you to the Pictures folder of your home folder.
You can also choose to hide the logo from appearing in the login window.
You can use the Restore option to put the original logo in the login window.