Image in footer (Twenty Eleven based child theme)

Hi

I’d like to put an image in the footer area. I’d like it to be the same width as the header (1000px).

I’m using a child theme of Twenty Eleven.

Does anyone know what code to put where to make this happen?
My site is here: https://handmadecrafthouse.co.uk.gridhosted.co.uk/ (still under construction!)

Many thanks in advance!
Tim