wp_img_tag_add_decoding_attr( string $image, string $context ): string

This function has been deprecated. Use wp_img_tag_add_loading_optimization_attrs() instead.

Adds decoding attribute to an img HTML tag.


The decoding attribute allows developers to indicate whether the browser can decode the image off the main thread (async), on the main thread (sync) or as determined by the browser (auto).

By default WordPress adds decoding="async" to images but developers can use the ‘wp_img_tag_add_decoding_attr’ filter to modify this to remove the attribute or set it to another accepted value.

See also


The HTML img tag where the attribute should be added.
Additional context to pass to the filters.


string Converted img tag with decoding attribute added.


function wp_img_tag_add_decoding_attr( $image, $context ) {
	_deprecated_function( __FUNCTION__, '6.4.0', 'wp_img_tag_add_loading_optimization_attrs()' );

	 * Only apply the decoding attribute to images that have a src attribute that
	 * starts with a double quote, ensuring escaped JSON is also excluded.
	if ( ! str_contains( $image, ' src="' ) ) {
		return $image;

	/** This action is documented in wp-includes/media.php */
	$value = apply_filters( 'wp_img_tag_add_decoding_attr', 'async', $image, $context );

	if ( in_array( $value, array( 'async', 'sync', 'auto' ), true ) ) {
		$image = str_replace( '<img ', '<img decoding="' . esc_attr( $value ) . '" ', $image );

	return $image;


apply_filters( ‘wp_img_tag_add_decoding_attr’, string|false|null $value, string $image, string $context )

Filters the decoding attribute value to add to an image. Default async.


6.4.0Use wp_img_tag_add_loading_optimization_attrs() instead.

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