Hi:
The problem is due to some invalid/messy HTML inside <div id="header">:
<DIV id=header>
<H1 class=style3><SPAN class=style9><A
href="http://www.studio7designs.com/index.html">STUDIO</A></SPAN><A
href="http://www.studio7designs.com/index.html"><SPAN class=style5>7</SPAN><SPAN
class=style9>DESIGNS</SPAN></A></H1>
<P><STRONG>"I can see you fly. You are an angel with wings, high above the
ground!"</STRONG><BR>(traditional haiku poem)</P>
</DIV>
Some of the tags above are nested improperly, causing Firefox to freak out and mess up anything below this DIV, including the alignment of the image slideshow. In fact, you can enter any random text in place of the slideshow, and it will be aligned incorrectly in Firefox due to the problem above.
To fix the problem, first, remove all the code inside the div, so it looks like:
<DIV id=header>
</DIV>
Then confirm that that fixes the alignment issue. Then slowly add back the desired code for the header div, making sure the HTML is clean and valid.