Question

wp_get_attachment_image( int $attachment_id,  string|array $size = 'thumbnail',  bool $icon = false,  string|array $attr = '' )

Get an HTML img element representing an image attachment

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description

While $size will accept an array, it is better to register a size with add_image_size() so that a cropped version is generated. It’s much more efficient than having to find the closest-sized image and then having the browser scale down the image.

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参数

$attachment_id

(int) (Required) Image attachment ID.

$size

(string|array) (Optional) Image size. Accepts any valid image size, or an array of width and height values in pixels (in that order).

Default value: 'thumbnail'

$icon

(bool) (Optional) Whether the image should be treated as an icon.

Default value: false

$attr

(string|array) (Optional) Attributes for the image markup.

Default value: ''

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返回值

(string) HTML img element or empty string on failure.

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源代码

File: wp-includes/media.php

function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = false, $attr = '') {
	$html = '';
	$image = wp_get_attachment_image_src($attachment_id, $size, $icon);
	if ( $image ) {
		list($src, $width, $height) = $image;
		$hwstring = image_hwstring($width, $height);
		$size_class = $size;
		if ( is_array( $size_class ) ) {
			$size_class = join( 'x', $size_class );
		}
		$attachment = get_post($attachment_id);
		$default_attr = array(
			'src'	=> $src,
			'class'	=> "attachment-$size_class size-$size_class",
			'alt'	=> trim( strip_tags( get_post_meta( $attachment_id, '_wp_attachment_image_alt', true ) ) ),
		);

		$attr = wp_parse_args( $attr, $default_attr );

		// Generate 'srcset' and 'sizes' if not already present.
		if ( empty( $attr['srcset'] ) ) {
			$image_meta = wp_get_attachment_metadata( $attachment_id );

			if ( is_array( $image_meta ) ) {
				$size_array = array( absint( $width ), absint( $height ) );
				$srcset = wp_calculate_image_srcset( $size_array, $src, $image_meta, $attachment_id );
				$sizes = wp_calculate_image_sizes( $size_array, $src, $image_meta, $attachment_id );

				if ( $srcset && ( $sizes || ! empty( $attr['sizes'] ) ) ) {
					$attr['srcset'] = $srcset;

					if ( empty( $attr['sizes'] ) ) {
$attr['sizes'] = $sizes;
					}
				}
			}
		}

		/**
		 * Filters the list of attachment image attributes.
		 *
		 * @since 2.8.0
		 *
		 * @param array        $attr       Attributes for the image markup.
		 * @param WP_Post      $attachment Image attachment post.
		 * @param string|array $size       Requested size. Image size or array of width and height values
		 *                                 (in that order). Default 'thumbnail'.
		 */
		$attr = apply_filters( 'wp_get_attachment_image_attributes', $attr, $attachment, $size );
		$attr = array_map( 'esc_attr', $attr );
		$html = rtrim("<img $hwstring");
		foreach ( $attr as $name => $value ) {
			$html .= " $name=" . '"' . $value . '"';
		}
		$html .= ' />';
	}

	return $html;
}

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更新日志

Version	description
2.5.0	Introduced.

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More Information

Usage

wp_get_attachment_image( $attachment_id, $size, $icon, $attr );

If the attachment is an image, the function returns an image at the specified size. For other attachments, the function returns a media icon if the $icon parameter is set to true.

To get attachment IDs dynamically in a template, you can use get_posts( array( 'post_type' => 'attachment' ) ), etc.

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相关函数

Uses

• wp-includes/media.php: wp_calculate_image_srcset()
• wp-includes/media.php: wp_calculate_image_sizes()
• wp-includes/functions.php: wp_parse_args()
• wp-includes/functions.php: absint()
• wp-includes/plugin.php: apply_filters()
• wp-includes/media.php: wp_get_attachment_image_src()
• wp-includes/media.php: wp_get_attachment_image_attributes
• wp-includes/media.php: image_hwstring()
• wp-includes/post.php: wp_get_attachment_metadata()
• wp-includes/post.php: get_post_meta()
• wp-includes/post.php: get_post()
Show 6 more uses Hide more uses

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Used By

• wp-includes/widgets/class-wp-widget-media-image.php: WP_Widget_Media_Image::render_media()
• wp-includes/general-template.php: get_custom_logo()
• wp-admin/includes/class-wp-media-list-table.php: WP_Media_List_Table::column_title()
• wp-admin/includes/post.php: _wp_post_thumbnail_html()
• wp-admin/includes/class-wp-comments-list-table.php: WP_Comments_List_Table::column_response()
• wp-includes/post-thumbnail-template.php: get_the_post_thumbnail()
• wp-includes/post-template.php: wp_get_attachment_link()
• wp-includes/media.php: gallery_shortcode()
• wp-includes/post.php: set_post_thumbnail()
Show 4 more used by Hide more used by

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User Contributed Notes

1. Skip to note content You must log in to vote on the helpfulness of this noteVote results for this note: 7You must log in to vote on the helpfulness of this note Contributed by Rinku Y

   wp_get_attachment_image function can accept four values as you can see:

   wp_get_attachment_image ( int $attachment_id, string|array $size = 'thumbnail', bool $icon = false, string|array $attr = '' )

   So i always use:

   <?php echo wp_get_attachment_image( get_the_ID(), array('700', '600'), "", array( "class" => "img-responsive" ) );  ?>

   Note: we can simply use get_the_ID() to pass id of active post. and here 700 is width and 600 is height of attachment image. we can also pass our class as array( “class” => “img-responsive” ).

To display all of the images and titles attached to a certain page and display them as a list of bullets you can use the following:

<ul>
	<?php if ( have_posts() ) : while ( have_posts() ) : the_post();

		$attachments = get_posts( array(
			'post_type'   => 'attachment',
			'numberposts' => -1,
			'post_status' => null,
			'post_parent' => $post->ID
		) );
		
		if ( $attachments ) {
			foreach ( $attachments as $attachment ) {
				?>
				<li><?php echo wp_get_attachment_image( $attachment->ID, 'full' ); ?>
					<p><?php echo apply_filters( 'the_title', $attachment->post_title ); ?></p>
				</li>
				<?php
			}
		}
	endwhile; endif; ?>
</ul>