Hi jacktheblack,
I am not sure how to move 4image database to new WP site, but if you want to change the no. of images in your RSS then you need to update your rss.php file.
Find :
@define('RSS_DEFAULT_ITEMS', 10);
@define('RSS_MAX_ITEMS', 30);
and change the numbers to your new numbers..
Hope this will help you ....