Description:
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1. Allocate an image resource $a.
2. Resample (scale) $a to a second resource $b.
3. Destroy $a.
4. Assign $a = $b.
5. Resample (crop) $a to a third resource $c.
6. Destroy $a.
7. Assign $a = $c.

For step 5 the initially allocated resource is used instead of the originally resampled one.


Reproduce code:
---------------
<?php

// http://schlitt.info/misc/gd/test_original.jpg
$res_1 = imagecreatefromjpeg( "test_original.jpg" );

$res_2 = imagecreatetruecolor( 200, 151 );

// Scale the image to 200x151
$res = imagecopyresampled(
    $res_2,     // dst_img
    $res_1,     // res_img
    0,          // dst_x
    0,          // dst_y
    0,          // src_x
    0,          // src_y
    200,        // dst_width
    151,        // dst_height
    150,        // src_width
    113         // src_height
);

// http://schlitt.info/misc/gd/test_scaled.jpg
imagejpeg( $res_2, "test_scaled.jpg" );

imagedestroy( $res_1 );

$res_1 = $res_2;

$res_3 = imagecreatetruecolor( 100, 100 );

// Crop the image to 100x100 selecting 50x150+50x150
$res = imagecopyresampled(
    $res_3,    // dst_img
    $res_1,    // res_img
    0,         // dst_x
    0,         // dst_y
    50,        // src_x
    50,        // src_y
    100,       // dst_width
    100,       // dst_height
    150,       // src_width
    150        // src_height
);

// http://schlitt.info/misc/gd/test_cropped.jpg
imagejpeg( $res_3, "test_cropped.jpg" );

imagedestroy( $res_1 );

$res_1 = $res_3;

// http://schlitt.info/misc/gd/test_final.jpg
imagejpeg( $res_1, "test_final.jpg" );

?>

Expected result:
----------------
test_cropped.jpg should be a cropped version of test_scaled.php

Actual result:
--------------
test_cropped.jpg is a cropped version of test_original.jpg