Description:
------------
I comple ImageMagick 6.3.6 , PHP 5.2.4 , and Apache/2.2.6, and Imagick 2.1.0-rc1 , and then I copy a real image to /tmp/test.jpg and then  run command php thumbnail.php which from examles , It got :
Fatal error: Uncaught exception 'ImagickException' with message 'Unable to read the file: /tmp/test.png' in /var/www/htdocs/thumbnail.php:11
Stack trace:
#0 /var/www/htdocs/thumbnail.php(11): Imagick->readimage('/tmp/test.png')
#1 {main}
  thrown in /var/www/htdocs/thumbnail.php on line 11

can you help ? what's the problem?

Reproduce code:
---------------
<?php
 
/*
	A simple example demonstrate thumbnail creation.
*/ 
 
/* Create the Imagick object */
$im = new Imagick();
 
/* Read the image file */
$im->readImage( '/tmp/test.png' );
 
/* Thumbnail the image ( width 100, preserve dimensions ) */
$im->thumbnailImage( 100, null );
 
/* Write the thumbail to disk */
$im->writeImage( '/tmp/th_test.png' );
 
/* Free resources associated to the Imagick object */
$im->destroy();
 
?

Expected result:
----------------
excutable

Actual result:
--------------
Fatal error: Uncaught exception 'ImagickException' with message 'Unable to read the file: /tmp/test.png' in /var/www/htdocs/thumbnail.php:11
Stack trace:
#0 /var/www/htdocs/thumbnail.php(11): Imagick->readimage('/tmp/test.png')
#1 {main}
  thrown in /var/www/htdocs/thumbnail.php on line 11