Use perfect titles, meta-key, meta description, and also some content needed in the site, not just images.
Meta tags is just a minor part of the seo now. There are lots of things that you would need to work on including the content, proper internal linking and external linking, sitemap and more. There are hundreds of sites who have stuffed meta keywords in them and the best ones. Who would yahoo rank. Atleast yahoo respects metatags to some extent. other engines consider it least.
You need to get links from other sites, so when Yahoo Slurp will crawl them, they will be shown for your site's backlinks.
The meta tags and on page factors are not enough, although required, for having some good web rankings in all search engines. Links are required and tens of ways you can follow for having them.
try using url submission, atleast it works for me http://www.google.co.in/search?hl=en&q=usrl+submit&btnG=Google+Search&meta=&aq=f&oq=