API for mime type in add_image_size, filtering mime output by image size, enable for core sizes

src/wp-admin/includes/image.php

@@ -505,13 +505,20 @@ function _wp_make_subsizes( $new_sizes, $file, $image_meta, $attachment_id, $mim
 		return array();
 	}
 
+	$original_mime_type = wp_get_image_mime( $file );
+
 	if ( ! $mime_type ) {
-		$mime_type = wp_get_image_mime( $file );
+		$mime_type = $original_mime_type;
 	}
 
 	// Check if any of the new sizes already exist.
 	if ( isset( $image_meta['sizes'] ) && is_array( $image_meta['sizes'] ) ) {
 		foreach ( $image_meta['sizes'] as $size_name => $size_meta ) {
+			// Check if the output mime is enabled for this image size.
+			if ( ! _wp_mime_type_available_for_image_size( $attachment_id, $size_name, $original_mime_type, $mime_type ) ) {
+				continue;
+			}
+
 			/*
 			 * Only checks "size name" so we don't override existing images even if the dimensions
 			 * don't match the currently defined size with the same name.
@@ -605,6 +612,21 @@ function _wp_make_subsizes( $new_sizes, $file, $image_meta, $attachment_id, $mim
 	return $image_meta;
 }
 
+/**
+ * Check whether mime type  output is available for a given size and mime type.
+ *
+ * @since 6.1.0
+ *
+ * @param int    $attachment_id Attachment ID.
+ * @param string $size_name     Size name to check.
+ * @return bool Whether the size is available for the given mime type.
+ */
+function _wp_mime_type_available_for_image_size( $attachment_id, $size_name, $source_mime, $destination_mime ) {
+	$image_mime_transforms = wp_upload_image_mime_transforms( $attachment_id, $size_name );
+
+	return isset( $image_mime_transforms[ $source_mime ] [ $destination_mime ] ) && image_size_supports_mime( $size_name, $destination_mime );
+}
+
 /**
  * Low-level function to create full-size images in additional mime types.
  *
@@ -1336,28 +1358,34 @@ function _copy_image_file( $attachment_id ) {
  * For example an `image/jpeg` should be converted into an `image/jpeg` and `image/webp`. The first type
  * is considered the primary output type for this image.
  *
+ * Called for each uploaded image to determine the list of mime types that should be converted into. Then,
+ * called again for each target image size as they are generated to see if the image should be converted into the mime type
+ * for that size.
+ *
  * @since 6.1.0
  *
- * @param $attachment_id int The attachment ID.
+ * @param int    $attachment_id  The attachment ID.
+ * @param string $image_size     The image size name. False when called on the image and target size is unavailable.
  * @return array An array of valid mime types, where the key is the source file mime type and the list of mime types to
  *               generate.
  */
-function wp_upload_image_mime_transforms( $attachment_id ) {
+function wp_upload_image_mime_transforms( $attachment_id, $image_size ) {
 	$image_mime_transforms = array(
 		'image/jpeg' => array( 'image/jpeg', 'image/webp' ),
 		'image/webp' => array( 'image/webp', 'image/jpeg' ),
 	);
 
 	/**
-	 * Filter to the output mime types for a given input mime type.
+	 * Filter to the output mime types for a given input mime type and image size.
 	 *
 	 * @since 6.1.0
 	 *
-	 * @param array $image_mime_transforms A map with the valid mime transforms where the key is the source file mime type
-	 *                                     and the value is one or more mime file types to generate.
-	 * @param int   $attachment_id         The ID of the attachment where the hook was dispatched.
+	 * @param array  $image_mime_transforms A map with the valid mime transforms where the key is the source file mime type
+	 *                                      and the value is one or more mime file types to generate.
+	 * @param int    $attachment_id         The ID of the attachment where the hook was dispatched.
+	 * @param string $image_size            The image size name. Optional.
 	 */
-	return (array) apply_filters( 'wp_upload_image_mime_transforms', $image_mime_transforms, $attachment_id );
+	return (array) apply_filters( 'wp_upload_image_mime_transforms', $image_mime_transforms, $attachment_id, $image_size );
 }
 
 /**
@@ -1371,7 +1399,7 @@ function wp_upload_image_mime_transforms( $attachment_id ) {
  * @return array An array with two entries, the primary mime type and the list of additional mime types.
  */
 function _wp_get_primary_and_additional_mime_types( $file, $attachment_id ) {
-	$image_mime_transforms = wp_upload_image_mime_transforms( $attachment_id );
+	$image_mime_transforms = wp_upload_image_mime_transforms( $attachment_id, false );
 	$original_mime_type    = wp_get_image_mime( $file );
 	$output_mime_types     = isset( $image_mime_transforms[ $original_mime_type ] ) ? $image_mime_transforms[ $original_mime_type ] : array( $original_mime_type );
 

src/wp-content/themes/twentyeleven/functions.php

@@ -227,9 +227,9 @@ function twentyeleven_setup() {
 		 * Add Twenty Eleven's custom image sizes.
 		 * Used for large feature (header) images.
 		 */
-		add_image_size( 'large-feature', $custom_header_support['width'], $custom_header_support['height'], true );
+		add_image_size( 'large-feature', $custom_header_support['width'], $custom_header_support['height'], true, true );
 		// Used for featured posts if a large-feature doesn't exist.
-		add_image_size( 'small-feature', 500, 300 );
+		add_image_size( 'small-feature', 500, 300, false, true );
 
 		// Default custom headers packaged with the theme. %s is a placeholder for the theme template directory URI.
 		register_default_headers(

src/wp-content/themes/twentyfourteen/functions.php

@@ -122,7 +122,7 @@ function twentyfourteen_setup() {
 		// Enable support for Post Thumbnails, and declare two sizes.
 		add_theme_support( 'post-thumbnails' );
 		set_post_thumbnail_size( 672, 372, true );
-		add_image_size( 'twentyfourteen-full-width', 1038, 576, true );
+		add_image_size( 'twentyfourteen-full-width', 1038, 576, true, true );
 
 		// This theme uses wp_nav_menu() in two locations.
 		register_nav_menus(

src/wp-content/themes/twentyseventeen/functions.php

@@ -56,9 +56,9 @@ function twentyseventeen_setup() {
 	 */
 	add_theme_support( 'post-thumbnails' );
 
-	add_image_size( 'twentyseventeen-featured-image', 2000, 1200, true );
+	add_image_size( 'twentyseventeen-featured-image', 2000, 1200, true, true );
 
-	add_image_size( 'twentyseventeen-thumbnail-avatar', 100, 100, true );
+	add_image_size( 'twentyseventeen-thumbnail-avatar', 100, 100, true, true );
 
 	// Set the default content width.
 	$GLOBALS['content_width'] = 525;

src/wp-content/themes/twentytwenty/functions.php

@@ -63,7 +63,7 @@ function twentytwenty_theme_support() {
 	set_post_thumbnail_size( 1200, 9999 );
 
 	// Add custom image size used in Cover Template.
-	add_image_size( 'twentytwenty-fullscreen', 1980, 9999 );
+	add_image_size( 'twentytwenty-fullscreen', 1980, 9999, false, true );
 
 	// Custom logo.
 	$logo_width  = 120;

src/wp-includes/media.php

@@ -275,29 +275,55 @@ function image_downsize( $id, $size = 'medium' ) {
  * Register a new image size.
  *
  * @since 2.9.0
+ * @since 6.1.0 Add the $output_mimes parameter.
  *
  * @global array $_wp_additional_image_sizes Associative array of additional image sizes.
  *
- * @param string     $name   Image size identifier.
- * @param int        $width  Optional. Image width in pixels. Default 0.
- * @param int        $height Optional. Image height in pixels. Default 0.
- * @param bool|array $crop   Optional. Image cropping behavior. If false, the image will be scaled (default),
- *                           If true, image will be cropped to the specified dimensions using center positions.
- *                           If an array, the image will be cropped using the array to specify the crop location.
- *                           Array values must be in the format: array( x_crop_position, y_crop_position ) where:
- *                               - x_crop_position accepts: 'left', 'center', or 'right'.
- *                               - y_crop_position accepts: 'top', 'center', or 'bottom'.
+ * @param string     $name         Image size identifier.
+ * @param int        $width        Optional. Image width in pixels. Default 0.
+ * @param int        $height       Optional. Image height in pixels. Default 0.
+ * @param bool|array $crop         Optional. Image cropping behavior. If false, the image will be scaled (default),
+ *                                 If true, image will be cropped to the specified dimensions using center positions.
+ *                                 If an array, the image will be cropped using the array to specify the crop location.
+ *                                 Array values must be in the format: array( x_crop_position, y_crop_position ) where:
+ *                                     - x_crop_position accepts: 'left', 'center', or 'right'.
+ *                                     - y_crop_position accepts: 'top', 'center', or 'bottom'.
+ * @param bool       $output_mimes Whether to output secondary mimes  for this image size. Default is null which will
+ *                                 throw a doing_it_wrong warning to warn developers they should set this value.
+ *                                 Default will be true in 6.2.
  */
-function add_image_size( $name, $width = 0, $height = 0, $crop = false ) {
+function add_image_size( $name, $width = 0, $height = 0, $crop = false, $output_mimes = null ) {
 	global $_wp_additional_image_sizes;
 
+	// For 6.1.x, warn developers about setting a value for $output_mimes.
+	if ( null === $output_mimes ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Passing the $output_mimes parameter to add_image_size is recommended.' ), '6.1.0' );
+	}
+
 	$_wp_additional_image_sizes[ $name ] = array(
-		'width'  => absint( $width ),
-		'height' => absint( $height ),
-		'crop'   => $crop,
+		'width'        => absint( $width ),
+		'height'       => absint( $height ),
+		'crop'         => $crop,
+		'output_mimes' => $output_mimes,
 	);
 }
 
+/**
+ * Check if an image size supports output in a specific mime type.
+ *
+ * @since 6.1.0
+ *
+ * @uses wp_get_additional_image_sizes()
+ *
+ * @param string $name      Image size identifier.
+ * @param string $mime_type The mime type to check.
+ * @return bool Whether the size supports the mime type for output.
+ */
+function image_size_supports_mime( $name, $mime_type ) {
+	$sizes = wp_get_additional_image_sizes();
+	return isset( $sizes[ $name ]['output_mimes'] ) && $sizes[ $name ]['output_mimes'];
+}
+
 /**
  * Check if an image size exists.
  *
@@ -345,7 +371,7 @@ function remove_image_size( $name ) {
  *                           An array can specify positioning of the crop area. Default false.
  */
 function set_post_thumbnail_size( $width = 0, $height = 0, $crop = false ) {
-	add_image_size( 'post-thumbnail', $width, $height, $crop );
+	add_image_size( 'post-thumbnail', $width, $height, $crop, true );
 }
 
 /**
@@ -890,11 +916,15 @@ function wp_get_registered_image_subsizes() {
 	$all_sizes        = array();
 
 	foreach ( get_intermediate_image_sizes() as $size_name ) {
-		$size_data = array(
-			'width'  => 0,
-			'height' => 0,
-			'crop'   => false,
-		);
+		$default_sizes = array( 'thumbnail', 'medium', 'medium_large', 'large' );
+		foreach ( get_intermediate_image_sizes() as $size_name ) {
+			$size_data = array(
+				'width'        => 0,
+				'height'       => 0,
+				'crop'         => false,
+				'output_mimes' => in_array( $size_name, $default_sizes, true ),
+			);
+		}
 
 		if ( isset( $additional_sizes[ $size_name ]['width'] ) ) {
 			// For sizes added by plugins and themes.
@@ -5292,9 +5322,9 @@ function wp_media_personal_data_exporter( $email_address, $page = 1 ) {
  */
 function _wp_add_additional_image_sizes() {
 	// 2x medium_large size.
-	add_image_size( '1536x1536', 1536, 1536 );
+	add_image_size( '1536x1536', 1536, 1536, false, true );
 	// 2x large size.
-	add_image_size( '2048x2048', 2048, 2048 );
+	add_image_size( '2048x2048', 2048, 2048, false, true );
 }
 
 /**

tests/phpunit/tests/media.php

@@ -1177,6 +1177,21 @@ public function test_has_image_size() {
 		remove_image_size( 'test-size' );
 	}
 
+	/**
+	 * @ticket 55443
+	 */
+	public function test_image_size_supports_mime() {
+		add_image_size( 'test-size', 200, 600, true, false );
+		$this->assertSame( false, image_size_supports_mime( 'test-size', 'image/webp' ) );
+		remove_image_size( 'test-size' );
+
+		add_image_size( 'test-size', 200, 600, true, true );
+		$this->assertSame( true, image_size_supports_mime( 'test-size', 'image/webp' ) );
+
+		// Clean up.
+		remove_image_size( 'test-size' );
+	}
+
 	/**
 	 * @ticket 30346
 	 */