will it lessen my available badwidth if i direct link my own files?

Yes, it will use up some of your bandwidth... but if it's small things, like avatars, it won't make that big a difference.

what if i have two accounts and i separated my images from my text files so if i have an image link the code would be like this...

<img src="http://blah blah blah.html">


instead of

<img src="THE IMAGE NAME.gif>

I'm not quite sure what you mean- any time you display an image or an HTML file is visited or you use any kind of file, you will use bandwidth. there's no way to get around that.