My guess is these URLs have your username as part of the URL thus you may have to sign in to your account to view their contents

If the URL to your web album has your Google ID number instead of your username signing in shouldn't be an issue

example to your public gallery https://picasaweb.google.com/103176925923805337179?noredirect=1

Just a thought ...have you left your Google Profile in 'Edit' mode ...another user had problems with links to his web albums because he had edited his Google Profile and had not saved the edits he made