Uploading to Picasa from iPhoto

Where (in what path and folder) do I find an album of pictures I would like to upload to Picasa using the Picasa uploader. When I go to Select Pictures from Your Computer in Picasa and point to my Pictiures folder, I see the iPhoto library but no pictures.

(It would be helpful if Apple developed a sharing option similat to the options to upload to Flickr, Facebook, etc. for Picasa.)