<div align="center"> is technically deprecated so prolly not a good idea to use it.
@lefever, I've not had the problem of the gallery forcing itself down the bottom. I've tested the current site I am working on across Firefox, IE7 and IE8, Chrome and Safari with no problems. The only thing I could think of at this point would be that it is an issue with the wordpress template. Have you tried changing it to something like Twentyten to see if that makes a difference?
Can you link me your site and I will have a look at it.
@nathan12343 To center align images I did this:
html:
<div id="container">
<div class="imagebox">
<img />
</div>
</div>
css:
div#container { width:100%; text-align:center; !important}
div.imagebox { width:150px; display:inline-block; margin:0 auto; !important}
(width can be whatever you need)
This works for all the browsers I test on except IE7. I haven't found a good solution for IE7 but I don't tend to bother with perfection for an outdated browser that only 7% of people still use (I replaced display:inline-block with float:left using an style-ie7.css stylesheet and conditional comments to target IE7 and IE7 users can lump it or leave it).
You can see an example of this here: http://demo.liquidsilver.net.nz/moniqueendt/gallery/ (album view listing galleries)
http://demo.liquidsilver.net.nz/moniqueendt/nggallery/page-8/album-1/gallery-1/ (Gallery view listing displaying images)