我打算开发一个视网膜就绪的主题。我上传了retina.min.js 在我的主题文件夹中：

http://riehling.mrcoolblog.com/wp-content/themes/riehling/js/retina.min.js

在我的functions.php, 我添加了以下代码：

add_action( \'wp_enqueue_scripts\', \'retina_support_enqueue_scripts\' );
function retina_support_enqueue_scripts() {
    wp_enqueue_script( \'retina_min_js\', get_template_directory_uri() . \'/js/retina.min.js\', null, \'\', true );
}

add_filter( \'wp_generate_attachment_metadata\', \'retina_support_attachment_meta\', 10, 2 );
function retina_support_attachment_meta( $metadata, $attachment_id ) {
    foreach ( $metadata as $key => $value ) {
        if ( is_array( $value ) ) {
            foreach ( $value as $image => $attr ) {
                if ( is_array( $attr ) )
                    retina_support_create_images( get_attached_file( $attachment_id ), $attr[\'width\'], $attr[\'height\'], true );
            }
        }
    }

    return $metadata;
}

function retina_support_create_images( $file, $width, $height, $crop = false ) {
    if ( $width || $height ) {
        $resized_file = wp_get_image_editor( $file );
        if ( ! is_wp_error( $resized_file ) ) {
            $filename = $resized_file->generate_filename( $width . \'x\' . $height . \'@2x\' ); 
            $resized_file->resize( $width * 2, $height * 2, $crop );
            $resized_file->save( $filename );

            $info = $resized_file->get_size();

            return array(
                \'file\' => wp_basename( $filename ),
                \'width\' => $info[\'width\'],
                \'height\' => $info[\'height\'],
            );
        }
    }
    return false;
}

add_filter( \'delete_attachment\', \'delete_retina_support_images\' );
function delete_retina_support_images( $attachment_id ) {
    $meta = wp_get_attachment_metadata( $attachment_id );
    $upload_dir = wp_upload_dir();
    $path = pathinfo( $meta[\'file\'] );
    foreach ( $meta as $key => $value ) {
        if ( \'sizes\' === $key ) {
            foreach ( $value as $sizes => $size ) {
                $original_filename = $upload_dir[\'basedir\'] . \'/\' . $path[\'dirname\'] . \'/\' . $size[\'file\'];
                $retina_filename = substr_replace( $original_filename, \'@2x.\', strrpos( $original_filename, \'.\' ), strlen( \'.\' ) );
                if ( file_exists( $retina_filename ) )
                    unlink( $retina_filename );
            }
        }
    }
}

它确实创建了一个@2x文件（尽管我很确定它会拉伸缩略图，而不是使用足够宽的源文件）。

但是，Retina JS脚本没有处理图像：

http://riehling.mrcoolblog.com/projets/scenographie/test-retina/

我正在使用<?php the_post_thumbnail( \'medium\' ); ?> 要显示图像和输出，如下所示：

<img width="236" height="310" src="http://riehling.mrcoolblog.com/wp-content/uploads/f2-236x310.jpg" class="attachment-medium size-medium wp-post-image" alt="Tiger" srcset="http://riehling.mrcoolblog.com/wp-content/uploads/f2-236x310.jpg 236w, http://riehling.mrcoolblog.com/wp-content/uploads/f2-768x1009.jpg 768w, http://riehling.mrcoolblog.com/wp-content/uploads/f2-472x620.jpg 472w, http://riehling.mrcoolblog.com/wp-content/uploads/f2.jpg 944w" sizes="(max-width: 236px) 100vw, 236px">

<?php echo get_the_post_thumbnail( get_the_ID(), \'thumbnail\', array( \'data-rjs\' => \'3\' ) ); ?>