Adding background image?

[mlthmp]

Im trying to add a background image to my current theme (using Startaza, with some different images) I want to try and add this image (http://mlthmp.com/wallpaper.jpg) as a background image. I've searched and havent been able to find anything to help. I've also looked into the theme's CSS with no luck. Any idea how I can add it?

[Shambles]

Try asking the theme author?

https://www.simplemachines.org/community/index.php?topic=557598.0