hi!. that's my question

i have fisubice theme and i would like insert an image as background, for default it has a light blue color...

how can i use this image? i don't know where to write the code, and i don't know what write for insert it

thanks for the possible answer

any help?

here is what I would do. Find a theme that already has an image for a background.
Then look at the css style sheet to see how they did it.

thx i thought about that