I really want to change the look of my lockscreen, but i dont know how. Plz help!

On my iPhone I can change the background of the lockscreen, or or with things like springboard I can change the theme. I wanted to do this on my mac so i downloaded Lockscreen 2. But I didn't want a passpattern, I would rather a password. So is there any way I can change the look of my dull-looking default lockscreen?