Footer image : automatic position ?

here is my website

Ohplastic.com
right now the image is extremely long.
I decided to cut the image into pieces,
1 the top header image
2 the bottom footer image

On my off line testing page,
the footer is at the top and expands the page horizontally.
I don’t want that.
I want the image to always appear at the bottom without actual positioning.
I realized if people comment ect it will need more room,
this is why i decided to use a hear img and a footer img.