Current imagemanager can`t execute image aliases which consist of different image handler`s filters. If you try to create this kind of image alias, your pages will be looped.

It happens because, when image manager selects next image handler, only MIME Types are compared (aliase`s output MIME Type and MIME Type suported by current image handler). But number of supported filters to current handler is ignored.

foreach ( $handlers as $handler ) {

	...

	$outputMimeData = $handler->outputMIMEType( $this, $currentMimeData, $destinationMimeData, $this->SupportedFormats, $aliasName );

	if ( $outputMimeData['name'] == $destinationMimeData['name'] )

	{

		$nextMimeData = $outputMimeData;

		$nextHandler = $handler;

		break;

	}

	...

}

For examlpe we have created new image handler nxcimagehandler. After this we have created new image alias my_imagealias which consist of 2 filters:

• ezimagegdhandler_filter1 (from ezimagegdhandler, its important that current filter doesn`t change MIME Type of image);

• nxcimagehandler_filter2 (from nxcimagehandler);

In this case, first time for $nextHandler will be assigned ezimagegdhandler. Filter ezimagegdhandler_filter1 will be applied to the image. And it will be removed from list of all filters which must be applied to the image.

...

$handlerFilters = array();

$leftoverFilters = array();

foreach ( $filters as $filter )

{

    if ( $nextHandler->isFilterSupported( $filter ) )

        $handlerFilters[] = $filter;

    else

        $leftoverFilters[] = $filter;

}

...

...

...

$filters = $leftoverFilters;

...

But second time for $nextHandler will be assigned ezimagegdhandler too! Because $destinationMimeData['name'] didn`t change after executing ezimagegdhandler_filter1.

Third time for $nextHandler will be assigned ezimagegdhandler too ... And here the looping is coming . nxcimagehandler_filter2 will be never applied.

To avoid this lopping trouble with several filters of different image handers you need to apply current patch.