Creating and Resize .gif image for Header

We are looding for someone to work on a .gif image file for the header in our Website. We are using Wordpress as the CMS. We need to have the file created and resized. We have 5 images that will need a slide show .gif and we need the header image to be 140 Pixels Tall and 660 Pixels Long. We need header adjusted to fit the new bigger .gif. Currently header is only 110 Pixels Tall.