Source

File: wp-admin/includes/image.php

function _load_image_to_edit_path( $attachment_id, $size = 'full' ) {
	$filepath = get_attached_file( $attachment_id );

	if ( $filepath && file_exists( $filepath ) ) {
		if ( 'full' !== $size ) {
			$data = image_get_intermediate_size( $attachment_id, $size );

			if ( $data ) {
				$filepath = path_join( dirname( $filepath ), $data['file'] );

				/**
				 * Filters the path to the current image.
				 *
				 * The filter is evaluated for all image sizes except 'full'.
				 *
				 * @since 3.1.0
				 *
				 * @param string $path          Path to the current image.
				 * @param string $attachment_id Attachment ID.
				 * @param string $size          Size of the image.
				 */
				$filepath = apply_filters( 'load_image_to_edit_filesystempath', $filepath, $attachment_id, $size );
			}
		}
	} elseif ( function_exists( 'fopen' ) && ini_get( 'allow_url_fopen' ) ) {
		/**
		 * Filters the image URL if not in the local filesystem.
		 *
		 * The filter is only evaluated if fopen is enabled on the server.
		 *
		 * @since 3.1.0
		 *
		 * @param string $image_url     Current image URL.
		 * @param string $attachment_id Attachment ID.
		 * @param string $size          Size of the image.
		 */
		$filepath = apply_filters( 'load_image_to_edit_attachmenturl', wp_get_attachment_url( $attachment_id ), $attachment_id, $size );
	}

	/**
	 * Filters the returned path or URL of the current image.
	 *
	 * @since 2.9.0
	 *
	 * @param string|bool $filepath      File path or URL to current image, or false.
	 * @param string      $attachment_id Attachment ID.
	 * @param string      $size          Size of the image.
	 */
	return apply_filters( 'load_image_to_edit_path', $filepath, $attachment_id, $size );
}