[Plugin: WordPress SEO by Yoast] per page keywords analysis

I’m new to WP and setting up a static site and using the SEO plugin. In the page edit area there is keyword analysis but it only seems to pickup data from the page itself, not the image meta tags or most importantly, the widgets. I guess this makes sense because we’re only in the page edit section ..

But Google doesn’t see it that way does it? Wouldn’t it search the text in widgets and image tags for a page too? I seriously need to re-think things if widgets are not picked up by a google bot.

Can anyone explain how the bot works? Does it search the database of page components, or does it build a page and then scan it, or what? There’s a lot more to this than I have previously considered.

Thanks for any response.

http://wordpress.org/extend/plugins/wordpress-seo/