Ahh... I see the problem now. Basically what is happening is that there are three images being manipulated:

onmouseover="document.imagename.src=image2.src" onmouseout="document.imagename.src=image1.src

(these are defined in the Javascript at the top of the file and "pre-loaded" for speed)

and the third

Your-image1.jpg which is referenced in your code. This loads when the page is first rendered. It doesnt exist which is why you are getting the red X. Once the mouse goes over it, Javascript changes the DOM value of the document to either OldVegas66.jpg or OldDowntown.jpg --- depending on whether you are in state mouseover or mouseout (respectively). So change your image tag that has "Your-image1" to be "OldVegas66.jpg" and life is good.