Background Picture Not displaying Correctly

Hi,

I am having serious problems with my background picture.

Chrome: Displays correctly at the start then deteriorates.
IE8: Split down the middle

I have been onto my hosting company and they told me to clear the cache and this worked (after a while) but obviously I need customers to see the site correctly. I had a previous problem with a temporary website i had in place before this.

A couple of unusual things happened before this started happening.

1. I changed the domain name on my hosting account
2. they noticed i was using wordpress and changed me from j2000 tomcat to linux hosting.

I wonder has anyone else had experience with this?