WordPress -> If Is Role Subscriber Show Image?

This <?php if ( current_user_can('contributor') ) : ?> only checks the users capabilities and is used like this <?php if ( current_user_can('edit_post') ) : ?>

You could write a function like this in functions.php:

function user_role_check( $role, $user_id = null ) {

  $user = wp_get_current_user();

    if ( empty( $user ) )
    return false;

  return in_array( $role, (array) $user->roles );
}

In your theme you would use it like this:

<?php if ( user_role_check( 'administrator' )): ?>

   Do this 

 <?php else: ?>

   Do this

<?php endif; ?>

Learn more about Roles and Capabilities: http://codex.wordpress.org/Roles_and_Capabilities