wp_editor_set_quality │ filter-hook │ WP 3.5.0

Allows changing the default image compression quality based on its MIME type and dimensions.

The image editor applies it when WP_Image_Editor::set_quality() is initialized or called without specifying a quality. A value explicitly passed to the method takes precedence over the filter.

During client-side image processing, WordPress also applies the filter separately to each generated size and passes the resulting quality to the browser.

Usage

add_filter( 'wp_editor_set_quality', 'wp_kama_editor_set_quality_filter', 10, 3 );

/**
 * Function for `wp_editor_set_quality` filter-hook.
 * 
 * @param int    $quality   Quality level between 1 (low) and 100 (high).
 * @param string $mime_type Image mime type.
 * @param array  $size      Dimensions of the image.
 *
 * @return int
 */
function wp_kama_editor_set_quality_filter( $quality, $mime_type, $size ){
	// filter...
	return $quality;
}

$quality(int)

Default compression quality from 1 — minimum to 100 — maximum.

$mime_type(string)

MIME type of the output image. For example, image/jpeg, image/webp, or image/avif.

$size(array)

Output image dimensions.

• width(int)
  Width in pixels.

• height(int)
  Height in pixels.

Examples

#1 Reduce quality for small JPEG images

Sets quality to 60 for JPEG images narrower than 300 pixels.

add_filter( 'wp_editor_set_quality', 'kama_set_small_jpeg_quality', 10, 3 );

function kama_set_small_jpeg_quality( $quality, $mime_type, $size ) {
	if (
		'image/jpeg' === $mime_type
		&& isset( $size['width'] )
		&& $size['width'] <= 300
	) {
		return 60;
	}

	return $quality;
}

#2 Different quality for each format

Sets a separate quality for JPEG, WebP, and AVIF.

add_filter( 'wp_editor_set_quality', 'kama_set_image_quality_by_format', 10, 3 );

function kama_set_image_quality_by_format( $quality, $mime_type, $size ) {
	$quality_by_format = [
		'image/jpeg' => 82,
		'image/webp' => 78,
		'image/avif' => 55,
	];

	return $quality_by_format[ $mime_type ] ?? $quality;
}