img contained in div not visible in FX

I am in the process of learning to write HTML that adjusts layout to user's
individual browser settings. I used to layout EVERYTHING with AP div tags. I
was taught in this forum that there are many people who "over ride" HTML font
sizes, background colors, text colors and window sizes, and that I should write
HTML that is more friendly to these folks. Well, I'm working on it. Things
are going alright, but I have run into a very unexpected glitch. I nested an
img tag inside an AP div tag inside another div with no defined position. The
img shows up just where expected in Opera and (believe it or not) Internet
Explorer. It is not showing up in Firefox, though. Please take a look and
help me understand what I've done wrong. the url is:
http://localhost/HolmesChiropractic/test2.html. Keep in mind that this is a
work in progress and certainly is not pretty right now. The img in question is
a stack of rocks about half way down the left side of the page. The img tag is
found on line 66. (or thereabouts if I make any changes before you see this.)
Thank you for your help. I'd love to be able to get to the bottom of this and
avoid this mistake in the future.

I composed my question last night just after I uploaded the page and then,
evidently, wasted my time by copying the wrong url. sorry, Malcom. Here is
the url that I meant to paste:
http://www.eversnug.com/holmeschiropractic/test2.html. I feel like a buffoon.
Thanks again for taking a look.

Thanks for taking another look, Malcom.

I've been looking into this some more, and I haven't found the cause of my
woes, yet. I imagine that this is simple enough that one of you forum
mainstays out there will spot the error in less than a minute.

any thoughts out there?

I still get a 404 - Not Found when I try the URL.

In a couple of places in this thread there is a period (".") following the url.
It is not supposed to be part of the url, but only part of proper sentence
structure. If you tried using one of those links, simply delete the period
from the end of the url once it is in your address bar. That should do it.

I solved the problem...finally. Maybe I'll get some input next time.
In case anyone is interested or would like to correct my theory:
It appears that of the three browsers with which I am testing, only Firefox
does not recognize negative z-index values. Pity. Any way to get Firefox to
recognize those negative values?

FF3 and IE7 look the same to me. Both show the stack of rocks.

Interesting. I'm running Firefox2. I wonder if displaying negative valued z-indexes is new to Firefox3. Does anyone here have that answer?