how do you submit your website images into the google image directory does anybody know? thanks

Google doesn't have an image directory

I guess he means the image search, in which case google automatically spiders the pictures on your site i think.

Give a proper alt tag and that way you can be in the image search as well but remember that image search of google is not upto the expectation of many of them.

<pedantic>
alt attribute
</pedantic>

The criteria appears to be mainly the page content and page title where the image is located

Why do have the need to have your images in G's image search anyway? So people can use them? Just curious.

you could try linking to your graphics with the keyword in the anchor text from a few pages with high page rank, that might help