page background fluid

[Gunshot]

I really need to build a fluid page background if possible

I have a left, Center and right gif.....with the center gif being all white
I know that I need to add some code to the additional CSS definitions, but I just can't seem to get it correct

I know the left and right Gifs have to be "repeat-y"
and the center gif has to be "repeat"

halfway there is about as close as I get

thanks for the help