Description:
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I'm using PHP 5.4.0 (it's not in the list above).  The test script attached used to work, but now I only get the one frame (as if I'd done writeImage()) saved.  If I do an echo, the image is animating so this (as far as I can see) is an issue only with writeImages().

Test script:
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$gif = new Imagick();
$gif->setFormat("gif");

foreach ($files as $file) {
    $frame = new Imagick();
    $frame->readImage($file);
    $gif->addImage($frame);
    $gif->setImageDelay(1);
}

$path = "/any/path/will/do/animation.gif";
$gif->writeImages($path,true);


Expected result:
----------------
A gif file written to the path specified that's animated.

Actual result:
--------------
A gif file written to the path specified that's not animated.