Japanese Nintendo Website Lets You Make Your Own Super Mario Maker Wallpaper
If you want to make your very own Super Mario Maker PC or cellphone wallpaper, there's an official website that will let you do it. Though it's in Japanese, you don't need any real knowledge of the language to access the wallpaper maker.
Simply go to http://mariomaker-wp.nintendo.co.jp, select the image of a computer monitor or a phone depending on what you want to make the wallpaper fit on, then get to creating. When you're done, just click on the Coursebot button on the bottom, then click on it one more time and your completed wallpaper will appear!