You say it passes validation but I saw a list with out <ul></ul> so I check and it does have some error nothing much but it does. Oddly enough (well not really) the list in question is the one your having problems with.

So place the <ul></ul> around it and if you don't want the bullets then add this style: list-style-type: none; to it and they both look the same in IE and FF.

As for the image the problem is with text-align: center; which centers the div that contains the image along with the text in IE but not in FF since the div is not text. You need to center the div for FF. That is simple enough just add margin-left: auto; and margin-right: auto; to div#gallerypicture and well you might want to eliminate margin:0 5px 0 5px;.

That should do it.

Future advice: I find testing in FF then verifing in IE alot better then the reverse since IE doesn't follow the rules as strictly as other browser which is one of the main reasons things like this happen.