There's no specific theme for the entries, just needs to be somehow related to Halloween. The only requirement is the size limitation. Your image should be no larger than 250kb (and that's being generous). If your images are a reasonable size (dimension-wise), then there should be absolutely no problem fitting this limit. If you have a problem getting your image to get under 250kb, ask for help. Again, do not wait until the last minute.
Other than that, you're pretty much free to do what you want. The judging will be based on relation to theme, skill, and creativity. If you have any questions or suggestions, make them now. If you wait too long, we won't be able to make any changes.
first place: pigeonkill - http://www.brianluk.com/gallery/pictures/smallclock.jpg
second place: darkreaver66 - http://home.cwru.edu/~nxl25/crap/samhain2.jpg
third place: eternallyrav - http://www.artoftherav.net/images/Ar...s/fat_love.jpg