ImageSizerEngineIMagick

Properties are inherited from ImageSizerEngine and configured via $config->imageSizerOptions in site/config.php or per-image options arrays. This module adds no public properties of its own.

getLibraryVersion()

Get the installed ImageMagick library version string.

$engine = $modules->get('ImageSizerEngineIMagick');
echo $engine->getLibraryVersion(); // e.g. "ImageMagick 7.1.0-57 n=7.1.0-57"

supportsFormat($format)

Check whether a given image format is supported by IMagick for both source and target.

if($engine->supportsFormat('WEBP')) {
    echo "WebP is supported!";
}

The $format argument is case-insensitive and should be a format string like 'PNG', 'JPG', 'WEBP', 'GIF', etc. Format suffixes like 'PNG24' or 'PNG24-alpha' are stripped to the base format before lookup. Results are cached in a static array for subsequent calls.

supported($action = 'imageformat')

Check whether IMagick is available and supports the requested action.

// Check if IMagick is available at all
if($engine->supported('install')) { /* ... */ }

// Check if current image format is supported
if($engine->supported('imageformat')) { /* ... */ }

// Check if WebP is supported
if($engine->supported('webp')) { /* ... */ }

The $action argument accepts:

This is the method ProcessWire core calls to auto-detect whether to use this engine.

getImagick($filename = '')

Create and return a new \Imagick instance, optionally loading an image file.

$imagick = $engine->getImagick('/path/to/image.jpg');
$imagick->resizeImage(300, 200, \Imagick::FILTER_LANCZOS, 1);

Throws a WireException if the file cannot be loaded.

reduceByHalf($dstFilename = '')

Reduce image dimensions by 50% using IMagick's minifyImage() method. This is more efficient than a standard resize for a 50% reduction.

$engine->prepare('/path/to/image.jpg');
$engine->reduceByHalf(); // overwrites original
// or save to a different file
$engine->reduceByHalf('/path/to/half.jpg');

Returns true on success, false on failure.

convertToGreyscale($dstFilename = '')

Convert an image to greyscale.

$engine->prepare('/path/to/image.jpg');
$engine->convertToGreyscale('/path/to/grey.jpg');

Returns true on success, false on failure.

convertToSepia($dstFilename = '', $sepia = 55)

Apply a sepia tone effect to an image.

$engine->prepare('/path/to/image.jpg');
$engine->convertToSepia('/path/to/sepia.jpg');

// Adjust the sepia strength (threshold: 0–100, default 55)
$engine->convertToSepia('/path/to/sepia.jpg', 80);

The $sepia argument accepts a value from 0 to 100, where higher values produce a stronger sepia effect. Internally, 35 is added before passing to \Imagick::sepiaToneImage().

Returns true on success, false on failure.

imSaveReady($im, $filename)

Called just before an image is saved to disk, after all transformations have been applied but before quality/compression settings take effect. The $im parameter is the \Imagick object, allowing you to apply final custom adjustments.

$wire->addHookAfter('ImageSizerEngineIMagick::imSaveReady', function($event) {
    $im = $event->arguments(0);    /** @var \IMagick $im */
    $filename = $event->arguments(1); /** @var string $filename */

    // Add a watermark or apply a final filter
    // Note: a clone of the original IMagick resource is passed,
    // so changes here affect the WebP copy (if any) too.
});

This hook fires for every image variation created. A clone of the IMagick resource is made before compression, so the original is preserved for WebP output if webpAdd is enabled.

install()

Called when the module is installed. Throws a WireException if IMagick is not available on the server. You can hook this to perform additional setup:

$wire->addHookAfter('ImageSizerEngineIMagick::install', function($event) {
    // Additional install logic
});

• Automatic fallback: ProcessWire's ImageSizer automatically detects whether ImageSizerEngineIMagick is installed and supported. If IMagick is not available, it falls back to ImageSizerEngineGD (the default GD-based engine).

• Quality difference: The IMagick engine uses a default quality of 80, which produces results visually similar to GD's 90. This is set in the constructor and can be overridden via $config->imageSizerOptions['quality'] in site/config.php.

• Color management: IMagick provides superior color profile handling compared to GD. ICC profiles, EXIF, IPTC, and XMP metadata are all processed and can be stripped or preserved. By default, non-ICC metadata is removed to reduce file size, matching GD behavior.

• Engine priority: This module sets enginePriority to 1 (first). If multiple engines are installed, the one with the lowest priority number that passes its supported() check is used. The ImageSizerEngineAnimatedGif module sets priority 9 so it only handles animated GIFs when no other engine does.

• WebP support: When WebP is supported by the installed IMagick version, the engine can automatically create WebP copies alongside standard image variations. Enable with the webpAdd or webpOnly properties.

• Sharpening: Unlike GD, the IMagick engine uses unsharpMaskImage() for sharpening. The sharpening parameters are adjusted based on the final image size (megapixels) and the selected sharpening mode.

• Image formats: Supported source formats are JPG, JPEG, PNG24, PNG, GIF, and GIF87. PNG8 is deliberately excluded due to bugs in some ImageMagick versions. WebP is supported as a target format when available.

• Module by Horst Nogajski, with contributions by Ryan Cramer. Licensed under MPL 2.0.

• Source file: wire/modules/Image/ImageSizerEngineIMagick/ImageSizerEngineIMagick.module