declare class mxImageBundle {
  constructor(alt: boolean);

  /**
   * Variable: images
   *
   * Maps from keys to images.
   */
  images: { [key: string]: { value: string; fallback: Function } };

  /**
   * Variable: alt
   *
   * Specifies if the fallback representation should be returned.
   */
  alt: boolean;

  /**
   * Function: putImage
   *
   * Adds the specified entry to the map. The entry is an object with a value and
   * fallback property as specified in the arguments.
   */
  putImage(key: string, value: string, fallback: Function): void;

  /**
   * Function: getImage
   *
   * Returns the value for the given key. This returns the value
   * or fallback, depending on <alt>. The fallback is returned if
   * <alt> is true, the value is returned otherwise.
   */
  getImage(key: string): string;
}