diff --git a/externs/olx.js b/externs/olx.js
index c72e9765c0..568a8cf13b 100644
--- a/externs/olx.js
+++ b/externs/olx.js
@@ -427,104 +427,6 @@ olx.source.VectorTileOptions.prototype.wrapX;
 olx.source.VectorTileOptions.prototype.transition;
 
 
-/**
- * @typedef {{url: (string|undefined),
- *     displayDpi: (number|undefined),
- *     metersPerUnit: (number|undefined),
- *     hidpi: (boolean|undefined),
- *     useOverlay: (boolean|undefined),
- *     projection: ol.ProjectionLike,
- *     ratio: (number|undefined),
- *     resolutions: (Array.<number>|undefined),
- *     imageLoadFunction: (ol.ImageLoadFunctionType|undefined),
- *     params: (Object|undefined)}}
- */
-olx.source.ImageMapGuideOptions;
-
-
-/**
- * The mapagent url.
- * @type {string|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.url;
-
-
-/**
- * The display resolution. Default is `96`.
- * @type {number|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.displayDpi;
-
-
-/**
- * The meters-per-unit value. Default is `1`.
- * @type {number|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.metersPerUnit;
-
-
-/**
- * Use the `ol.Map#pixelRatio` value when requesting the image from the remote
- * server. Default is `true`.
- * @type {boolean|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.hidpi;
-
-
-/**
- * If `true`, will use `GETDYNAMICMAPOVERLAYIMAGE`.
- * @type {boolean|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.useOverlay;
-
-
-/**
- * Projection.
- * @type {ol.ProjectionLike}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.projection;
-
-
-/**
- * Ratio. `1` means image requests are the size of the map viewport, `2` means
- * twice the width and height of the map viewport, and so on. Must be `1` or
- * higher. Default is `1`.
- * @type {number|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.ratio;
-
-
-/**
- * Resolutions. If specified, requests will be made for these resolutions only.
- * @type {Array.<number>|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.resolutions;
-
-
-/**
- * Optional function to load an image given a URL.
- * @type {ol.ImageLoadFunctionType|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.imageLoadFunction;
-
-
-/**
- * Additional parameters.
- * @type {Object|undefined}
- * @api
- */
-olx.source.ImageMapGuideOptions.prototype.params;
-
-
 /**
  * @typedef {{cacheSize: (number|undefined),
  *     layer: string,
diff --git a/src/ol/source/ImageMapGuide.js b/src/ol/source/ImageMapGuide.js
index fb59f00210..10cc47155c 100644
--- a/src/ol/source/ImageMapGuide.js
+++ b/src/ol/source/ImageMapGuide.js
@@ -10,6 +10,24 @@ import {assign} from '../obj.js';
 import ImageSource, {defaultImageLoadFunction} from '../source/Image.js';
 import {appendParams} from '../uri.js';
 
+/**
+ * @typedef {Object} Options
+ * @property {string} [url] The mapagent url.
+ * @property {number} [displayDpi=96] The display resolution.
+ * @property {number} [metersPerUnit=1] The meters-per-unit value.
+ * @property {boolean} [hidpi=true] Use the `ol.Map#pixelRatio` value when requesting
+ * the image from the remote server.
+ * @property {boolean} [useOverlay] If `true`, will use `GETDYNAMICMAPOVERLAYIMAGE`.
+ * @property {ol.ProjectionLike} projection Projection.
+ * @property {number} [ratio=1] Ratio. `1` means image requests are the size of the map viewport, `2` means
+ * twice the width and height of the map viewport, and so on. Must be `1` or higher.
+ * @property {Array.<number>} [resolutions] Resolutions.
+ * If specified, requests will be made for these resolutions only.
+ * @property {ol.ImageLoadFunctionType} [imageLoadFunction] Optional function to load an image given a URL.
+ * @property {Object} [params] Additional parameters.
+ */
+
+
 /**
  * @classdesc
  * Source for images from Mapguide servers
@@ -17,7 +35,7 @@ import {appendParams} from '../uri.js';
  * @constructor
  * @fires ol.source.Image.Event
  * @extends {ol.source.Image}
- * @param {olx.source.ImageMapGuideOptions} options Options.
+ * @param {module:ol/source/ImageMapGuide~Options=} options ImageMapGuide options.
  * @api
  */
 const ImageMapGuide = function(options) {