SIS_Admin_Main::wp_generate_attachment_metadata_custom PHP Method

    public static function wp_generate_attachment_metadata_custom($attachment_id, $file, $thumbnails = null)
    {
        $attachment = get_post($attachment_id);
        $meta_datas = get_post_meta($attachment_id, '_wp_attachment_metadata', true);
        $metadata = array();
        if (preg_match('!^image/!', get_post_mime_type($attachment)) && file_is_displayable_image($file)) {
            $imagesize = getimagesize($file);
            $metadata['width'] = $imagesize[0];
            $metadata['height'] = $imagesize[1];
            list($uwidth, $uheight) = wp_constrain_dimensions($metadata['width'], $metadata['height'], 128, 96);
            $metadata['hwstring_small'] = "height='{$uheight}' width='{$uwidth}'";
            // Make the file path relative to the upload dir
            $metadata['file'] = _wp_relative_upload_path($file);
            // make thumbnails and other intermediate sizes
            global $_wp_additional_image_sizes;
            foreach (get_intermediate_image_sizes() as $s) {
                $sizes[$s] = array('width' => '', 'height' => '', 'crop' => false);
                if (isset($_wp_additional_image_sizes[$s]['width'])) {
                    $sizes[$s]['width'] = intval($_wp_additional_image_sizes[$s]['width']);
                } else {
                    $sizes[$s]['width'] = get_option("{$s}_size_w");
                }
                // For default sizes set in options
                if (isset($_wp_additional_image_sizes[$s]['height'])) {
                    $sizes[$s]['height'] = intval($_wp_additional_image_sizes[$s]['height']);
                } else {
                    $sizes[$s]['height'] = get_option("{$s}_size_h");
                }
                // For default sizes set in options
                if (isset($_wp_additional_image_sizes[$s]['crop'])) {
                    $sizes[$s]['crop'] = intval($_wp_additional_image_sizes[$s]['crop']);
                } else {
                    $sizes[$s]['crop'] = get_option("{$s}_crop");
                }
                // For default sizes set in options
            }
            $sizes = apply_filters('intermediate_image_sizes_advanced', $sizes);
            // Only if not all sizes
            if (isset($thumbnails) && is_array($thumbnails) && isset($meta_datas['sizes']) && !empty($meta_datas['sizes'])) {
                // Fill the array with the other sizes not have to be done
                foreach ($meta_datas['sizes'] as $name => $fsize) {
                    $metadata['sizes'][$name] = $fsize;
                }
            }
            foreach ($sizes as $size => $size_data) {
                if (isset($thumbnails)) {
                    if (!in_array($size, $thumbnails)) {
                        continue;
                    }
                }
                $resized = image_make_intermediate_size($file, $size_data['width'], $size_data['height'], $size_data['crop']);
                if (isset($meta_datas['size'][$size])) {
                    // Remove the size from the orignal sizes for after work
                    unset($meta_datas['size'][$size]);
                }
                if ($resized) {
                    $metadata['sizes'][$size] = $resized;
                }
            }
            // fetch additional metadata from exif/iptc
            $image_meta = wp_read_image_metadata($file);
            if ($image_meta) {
                $metadata['image_meta'] = $image_meta;
            }
        }
        return apply_filters('wp_generate_attachment_metadata', $metadata, $attachment_id);
    }