Oh dear...... this is a simple matter of metrics. If you have a graphic that is a fixed width size, then its container needs to be the same size otherwise it won't fill it. If you try and stretch a gradient graphic, you will distort the gradient. Do you even know how computer graphics and pixels work?
No, I'm a web developer in the UK and I offer any advice on these forums because its how I was able to learn how things work and I try to give a little bit back where I can to people who genuinely want to understand what they are doing in order to better service their customers. I enjoy coming onto the forums and even after 6 years I still find myself learning things that help me to provide better solutions. I believe its called a community.
You want a solution? If you build websites for a living, and charge people for the service, then spend some time understanding what you are actually doing :-)
I'm always happy to help, but only if the recipient wants to be helped.
Deeeep breath..... and on with my evening :-)