It's the relative URLs path issue, what you got there only work on the index. To fix it, just use absolute path or use WP template tag to correctly pull the image.
In this case, it makes more sense to just use absolute path to that logo.
<img alt="Space 4 Art Logo" src="http://www.sdspace4art.org/wp-content/uploads/2013/09/LOGO-HI-RES-copy.png" />