Add Photo Slideshow Behind Web Elements

We have a pretty much completed website except for one modification. We have an image background at the top and a couple of navigational menus float over it along with a trip widget. We need to convert that static image to a set of 5 rotating images but keep it so that it is a background where the current elements continue to float above it. We have the five images, all around 100K in size. If you might be able to help with reducing the size without losing clarity, that would help as well. We have one more element that needs work and that is adding an RSS feed to the page and have it blend with the rest of the site. Everything we use tends to not allow the customization we want. In your notes, please break this out into two separate quotes. We know we want the slideshow but we may not do the RSS feed. ** PLEASE HAVE EXPERIENCE CREATING PHOTO ROTATION SLIDESHOWS BEFORE YOU BID. SITE IS IN HTML/CSS. WE DO NOT WANT THIS CONVERTED TO FLASH. **