Style Manager for your style, go to Stylevars, then body_background, in the
Common section
Then…
Example,
[CODE]url([FONT=Courier New][COLOR=#ff8000]path/to/image[/COLOR][/FONT])[/CODE] or the URL to the image.
Background repeat = repeat-x (in my case)
units = px (in my case)
Background Image Horizontal Offset = 0 (in my case)
Background Image Vertical Offset = 0 (in my case)
You have to set all these variables or the image wont show.
To do a fixed center background image :
[CODE][COLOR=#000000][FONT=Courier New][COLOR=#0000bb]url[/COLOR][COLOR=#007700]([/COLOR][COLOR=#0000bb]http[/COLOR][COLOR=#007700]:[/COLOR][COLOR=#ff8000]//path/to/image) fixed [/COLOR][/FONT][/COLOR][/CODE]
It is also a good idea to change the Background Color to match your image.