message: move validation logic inside images
diff: @@ -69,6 +69,16 @@ export class PassImages {
  );
  }
  + /**
  + * Checks that all required images is set or throws elsewhere
  + */
  + validate(): void {
  + // icon is required
  + assert.ok(this.icon, 'icon image is required');
  + // logo is required
  + assert.ok(this.logo, 'logo image is required');
  + }
  +
  /**
  * Load all images from the specified directory. Only supported images are
  * loaded, nothing bad happens if directory contains other files.
  