In my application i display the image of user by giving the physical path of the directories like http://www.example.com/user_images/abcdefghijk.jpg
But i dont want to
in php you can save a variable in session and append it to image's path like
<img src="php_function.php?token=1234" />
and in php file get the image reading from session its actual path and return the content by file_get_contents
here is the source http://hashmode.com/hide-image-path-php/9
In PHP you can use GD library to read the image. So the only way you need to create a image.php file & use the following code,
<?php
$imagepath="your image physical path";
$image=imagecreatefromjpeg($imagepath);
header('Content-Type: image/jpeg');
imagejpeg($image);
?>
this is for jpg image for all other images you can use different functions fo GD library.
So Gravtar.com uses the above way to display the image :)
In ROR you can use Rmagick gem to read the image & display the image with the same way.
Thanks