WordPress.org

What can I embed?

You can embed individual photos -- embedding an album or a random selection of user's photos isn't supported: there are a lot of other plugins that can do that.

How do I embed them?

Include the url of the photo on a line of its own or between [embed] tags and the photo will be embedded, as described in the Codex Embeds page.

Why does it still show an old version of my photo?

The plugin caches the photo url so that it does not have to query Google every time a visitor views the page. This cache is cleared every time the post is saved, so if you change the photo on Picasa, you may have to save the post again to see these changes in the post.

Is the plugin broken?

1. Are you using WordPress > 2.9?
2. Have you enabled auto embeds in the Settings -> Media page?
3. Is the image you're trying to embed visible to the public?
4. Have you used the right url -- only urls in the form http://picasaweb.google.com/{user}/{album}#{photo} are supported (e.g. http://picasaweb.google.com/linmep/PicAutumn09#5410318127990876210). Search URLs (e.g. http://picasaweb.google.com/lh/view?q=leaf&psc=G&filter=1#5325823428363864770) don't work.

If you can answer "yes" to the above the plugin may indeed be broken.