I'm still allowing pics on html at my link list, but I'm not sure how much longer this will be true.
When building if you always name the pics the exact same thing and use relative paths in your code plus leave off the height and width tags you can just drop in new pics when reusing your templates.
As far as outgoing links on your pages 3 seems to be pretty much the standard, but on my own stuff I rarely use more then one ad per page.
Also 10 min to 15 max pics per page is pretty much what most people do.
You can make as many sub folders on your domain as you see fit.
I seem to remember that you wanted a Windows server. What are you going to do to prevent hotlinking of your images since htaccess doesn't work with Windows servers?