One question is will this be held on afn or hott? From what I've seen so far, you can do larger images on hott. There are a number of good reasons for limiting image size from needing larger servers to store the pics= more $$$ to lots of large images can slow a site to a crawl.
That said, to post the best images on afn, you need to resize them so that the longest dimension is 1000 pixels at 96 dpi. Now this is key---Save it as a .png file. Anytime you have a jpeg and make changes to it, it will recompress the file and information will be lost resulting in a lower quality image.
When I get a minute I'll try to figure sizing for hott.
The one thing that will make a huge difference in your pics is to use a tripod.
The other is if you have to use the on camera flash-- stick a piece of toilet paper over it. That will cut down the glare you get.
I'm gonna kick myself in the butt for this but
For this battle only, if you don't have the software or ability to resize images, you can send your final pics to me and I'll take care of it