First off, you gotta have a paid account to be able to use a custom mood theme.
  	 

(1) Download this zip file and unzip it to a folder.

(2) Upload all images to your webspace. 

(3) Log in to LiveJournal and go to the LJ command console, write
    moodtheme_create "Veronica Mars" 

(4) The next page should say: Success. Your new moodthemeid = ......
    It's going to show you the name of your theme and a number. Jot the number down somewhere and 
    DON'T close the command console.

(5) Download this text file.

(6) Switch 123 with the number you got earlier. Also switch the http://www.yoursitehere.com with
    where you are storing the pictures.

(7) Copy and paste everything from the modified text into the command console, and hit enter!

(8) When the page comes back, make sure you see 'data inserted' for each mood. If not, you might of made a mistake,
    and you gonna have to go back and fix it.

(9) Go to the modify journal section, and pick Veronica Mars from the menu. Click on the save button,
    and you are all done!