Images not displaying properly…

Hi – new to WordPress and these forums, and I’m a relative newbie to coding. So thanks in advance for the help and patience!

I’m attempting to build a site for a friend – the url is
http://aolff.org/wordpress/

In Firefox, my header looks great. In IE and Opera, the central logo doesn’t display at all. I created a new class in the style sheet (masthead2) and then added that in the header.php file – that’s the only way I could make it display at all in FF.

And then, I’d like to be able to place ads with images in the right and left columns. The text is displaying properly, but the images don’t appear in FF, IE, or Opera.

I’m attempting the standard insertion (img src = ” ” ) to display them – is there a different way to code this for wordpress?

You can see more clearly what I am attempting on the original site – http://aolff.org

I’m trying to switch the entire site over to be wordpress driven!

Thanks in advance for the help…