Header Image Problems

Hello, I am having some problems with my header image. In safari the image loads fine, but it doesn’t at all in firefox. I’ve read a couple other threads and tried the solutions, but no luck. I tried changing the image to a small 10 x 10 image and it works, so I believe it has something to do with the image. I don’t know how small it has to be but ive tried .png, .bmp formats with no luck. The w3 validator also says my site has 5 errors, but I have no idea why or where to find these errors (I know php, html, etc. but I don’t know wordpress very well.)

My site is livingmadegreen.com.

Thanks!