Ideally, you'd chown a folder to the user account running Apache. This might be 'apache' or 'www-data' or something else, depending on your environment. If the folder is chown'd by that user, you'd only need a permission of 700.
You might also want to check the file upload path in your php.ini file. It may upload the file with a unique filename into /tmp/ and then you'd use move_uploaded_file() to move the image to your 'images' folder.
As far as the .htaccess is concerned, you could also just write a simple index.php script that redirects to some other page on the site, like:
header("Location: /") ;
So if someone tries to view yourdomain.com/images/ it'll just bounce them back to yourdomain.com