diff --git a/wp-admin/js/widgets/media-gallery-widget.js b/wp-admin/js/widgets/media-gallery-widget.js
index 7d0d191c20..ebba81cf86 100644
--- a/wp-admin/js/widgets/media-gallery-widget.js
+++ b/wp-admin/js/widgets/media-gallery-widget.js
@@ -201,7 +201,7 @@
 			});
 
 			mediaFrameProps = control.mapModelToMediaFrameProps( control.model.toJSON() );
-			selection.gallery = new Backbone.Model( _.pick( mediaFrameProps, 'columns', 'link', 'size', '_orderbyRandom' ) );
+			selection.gallery = new Backbone.Model( mediaFrameProps );
 			if ( mediaFrameProps.size ) {
 				control.displaySettings.set( 'size', mediaFrameProps.size );
 			}
diff --git a/wp-admin/js/widgets/media-gallery-widget.min.js b/wp-admin/js/widgets/media-gallery-widget.min.js
index cf62f20786..ec64b7d3cc 100644
--- a/wp-admin/js/widgets/media-gallery-widget.min.js
+++ b/wp-admin/js/widgets/media-gallery-widget.min.js
@@ -1 +1 @@
-!function(a){"use strict";var b,c,d;d=wp.media.view.MediaFrame.Post.extend({createStates:function(){this.states.add([new wp.media.controller.Library({id:"gallery",title:wp.media.view.l10n.createGalleryTitle,priority:40,toolbar:"main-gallery",filterable:"uploaded",multiple:"add",editable:!0,library:wp.media.query(_.defaults({type:"image"},this.options.library))}),new wp.media.controller.GalleryEdit({library:this.options.selection,editing:this.options.editing,menu:"gallery"}),new wp.media.controller.GalleryAdd])}}),b=a.MediaWidgetModel.extend({}),c=a.MediaWidgetControl.extend({events:_.extend({},a.MediaWidgetControl.prototype.events,{"click .media-widget-gallery-preview":"editMedia"}),initialize:function(b){var c=this;a.MediaWidgetControl.prototype.initialize.call(c,b),_.bindAll(c,"updateSelectedAttachments","handleAttachmentDestroy"),c.selectedAttachments=new wp.media.model.Attachments,c.model.on("change:ids",c.updateSelectedAttachments),c.selectedAttachments.on("change",c.renderPreview),c.selectedAttachments.on("reset",c.renderPreview),c.updateSelectedAttachments(),wp.customize&&wp.customize.previewer&&c.selectedAttachments.on("change",function(){wp.customize.previewer.send("refresh-widget-partial",c.model.get("widget_id"))})},updateSelectedAttachments:function(){var a,b,c,d,e,f=this;a=f.model.get("ids"),b=_.pluck(f.selectedAttachments.models,"id"),c=_.difference(b,a),_.each(c,function(a){f.selectedAttachments.remove(f.selectedAttachments.get(a))}),d=_.difference(a,b),d.length&&(e=wp.media.query({order:"ASC",orderby:"post__in",perPage:-1,post__in:a,query:!0,type:"image"}),e.more().done(function(){f.selectedAttachments.reset(e.models)}))},renderPreview:function(){var a,b,c,d=this;a=d.$el.find(".media-widget-preview"),b=wp.template("wp-media-widget-gallery-preview"),c=d.previewTemplateProps.toJSON(),c.attachments={},d.selectedAttachments.each(function(a){c.attachments[a.id]=a.toJSON()}),a.html(b(c))},isSelected:function(){var a=this;return!a.model.get("error")&&a.model.get("ids").length>0},editMedia:function(){var a,b,c,e=this;a=new wp.media.model.Selection(e.selectedAttachments.models,{multiple:!0}),c=e.mapModelToMediaFrameProps(e.model.toJSON()),a.gallery=new Backbone.Model(_.pick(c,"columns","link","size","_orderbyRandom")),c.size&&e.displaySettings.set("size",c.size),b=new d({frame:"manage",text:e.l10n.add_to_widget,selection:a,mimeType:e.mime_type,selectedDisplaySettings:e.displaySettings,showDisplaySettings:e.showDisplaySettings,metadata:c,editing:!0,multiple:!0,state:"gallery-edit"}),wp.media.frame=b,b.on("update",function(a){var c,d=b.state();c=a||d.get("selection"),c&&(c.gallery&&e.model.set(e.mapMediaToModelProps(c.gallery.toJSON())),e.selectedAttachments.reset(c.models),e.model.set({ids:_.pluck(c.models,"id")}))}),b.$el.addClass("media-widget"),b.open(),a&&a.on("destroy",e.handleAttachmentDestroy)},selectMedia:function(){var a,b,c,e=this;a=new wp.media.model.Selection(e.selectedAttachments.models,{multiple:!0}),c=e.mapModelToMediaFrameProps(e.model.toJSON()),c.size&&e.displaySettings.set("size",c.size),b=new d({frame:"select",text:e.l10n.add_to_widget,selection:a,mimeType:e.mime_type,selectedDisplaySettings:e.displaySettings,showDisplaySettings:e.showDisplaySettings,metadata:c,state:"gallery"}),wp.media.frame=b,b.on("update",function(a){var c,d=b.state();c=a||d.get("selection"),c&&(c.gallery&&e.model.set(e.mapMediaToModelProps(c.gallery.toJSON())),e.selectedAttachments.reset(c.models),e.model.set({ids:_.pluck(c.models,"id")}))}),b.$el.addClass("media-widget"),b.open(),a&&a.on("destroy",e.handleAttachmentDestroy),b.$el.find(":focusable:first").focus()},handleAttachmentDestroy:function(a){var b=this;b.model.set({ids:_.difference(b.model.get("ids"),[a.id])})}}),a.controlConstructors.media_gallery=c,a.modelConstructors.media_gallery=b}(wp.mediaWidgets);
\ No newline at end of file
+!function(a){"use strict";var b,c,d;d=wp.media.view.MediaFrame.Post.extend({createStates:function(){this.states.add([new wp.media.controller.Library({id:"gallery",title:wp.media.view.l10n.createGalleryTitle,priority:40,toolbar:"main-gallery",filterable:"uploaded",multiple:"add",editable:!0,library:wp.media.query(_.defaults({type:"image"},this.options.library))}),new wp.media.controller.GalleryEdit({library:this.options.selection,editing:this.options.editing,menu:"gallery"}),new wp.media.controller.GalleryAdd])}}),b=a.MediaWidgetModel.extend({}),c=a.MediaWidgetControl.extend({events:_.extend({},a.MediaWidgetControl.prototype.events,{"click .media-widget-gallery-preview":"editMedia"}),initialize:function(b){var c=this;a.MediaWidgetControl.prototype.initialize.call(c,b),_.bindAll(c,"updateSelectedAttachments","handleAttachmentDestroy"),c.selectedAttachments=new wp.media.model.Attachments,c.model.on("change:ids",c.updateSelectedAttachments),c.selectedAttachments.on("change",c.renderPreview),c.selectedAttachments.on("reset",c.renderPreview),c.updateSelectedAttachments(),wp.customize&&wp.customize.previewer&&c.selectedAttachments.on("change",function(){wp.customize.previewer.send("refresh-widget-partial",c.model.get("widget_id"))})},updateSelectedAttachments:function(){var a,b,c,d,e,f=this;a=f.model.get("ids"),b=_.pluck(f.selectedAttachments.models,"id"),c=_.difference(b,a),_.each(c,function(a){f.selectedAttachments.remove(f.selectedAttachments.get(a))}),d=_.difference(a,b),d.length&&(e=wp.media.query({order:"ASC",orderby:"post__in",perPage:-1,post__in:a,query:!0,type:"image"}),e.more().done(function(){f.selectedAttachments.reset(e.models)}))},renderPreview:function(){var a,b,c,d=this;a=d.$el.find(".media-widget-preview"),b=wp.template("wp-media-widget-gallery-preview"),c=d.previewTemplateProps.toJSON(),c.attachments={},d.selectedAttachments.each(function(a){c.attachments[a.id]=a.toJSON()}),a.html(b(c))},isSelected:function(){var a=this;return!a.model.get("error")&&a.model.get("ids").length>0},editMedia:function(){var a,b,c,e=this;a=new wp.media.model.Selection(e.selectedAttachments.models,{multiple:!0}),c=e.mapModelToMediaFrameProps(e.model.toJSON()),a.gallery=new Backbone.Model(c),c.size&&e.displaySettings.set("size",c.size),b=new d({frame:"manage",text:e.l10n.add_to_widget,selection:a,mimeType:e.mime_type,selectedDisplaySettings:e.displaySettings,showDisplaySettings:e.showDisplaySettings,metadata:c,editing:!0,multiple:!0,state:"gallery-edit"}),wp.media.frame=b,b.on("update",function(a){var c,d=b.state();c=a||d.get("selection"),c&&(c.gallery&&e.model.set(e.mapMediaToModelProps(c.gallery.toJSON())),e.selectedAttachments.reset(c.models),e.model.set({ids:_.pluck(c.models,"id")}))}),b.$el.addClass("media-widget"),b.open(),a&&a.on("destroy",e.handleAttachmentDestroy)},selectMedia:function(){var a,b,c,e=this;a=new wp.media.model.Selection(e.selectedAttachments.models,{multiple:!0}),c=e.mapModelToMediaFrameProps(e.model.toJSON()),c.size&&e.displaySettings.set("size",c.size),b=new d({frame:"select",text:e.l10n.add_to_widget,selection:a,mimeType:e.mime_type,selectedDisplaySettings:e.displaySettings,showDisplaySettings:e.showDisplaySettings,metadata:c,state:"gallery"}),wp.media.frame=b,b.on("update",function(a){var c,d=b.state();c=a||d.get("selection"),c&&(c.gallery&&e.model.set(e.mapMediaToModelProps(c.gallery.toJSON())),e.selectedAttachments.reset(c.models),e.model.set({ids:_.pluck(c.models,"id")}))}),b.$el.addClass("media-widget"),b.open(),a&&a.on("destroy",e.handleAttachmentDestroy),b.$el.find(":focusable:first").focus()},handleAttachmentDestroy:function(a){var b=this;b.model.set({ids:_.difference(b.model.get("ids"),[a.id])})}}),a.controlConstructors.media_gallery=c,a.modelConstructors.media_gallery=b}(wp.mediaWidgets);
\ No newline at end of file
diff --git a/wp-includes/version.php b/wp-includes/version.php
index dfb373a848..1900d9a5dc 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-beta3-41950';
+$wp_version = '4.9-beta3-41951';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
diff --git a/wp-includes/widgets/class-wp-widget-media-gallery.php b/wp-includes/widgets/class-wp-widget-media-gallery.php
index 3ac9cc910c..13ee9c2d6e 100644
--- a/wp-includes/widgets/class-wp-widget-media-gallery.php
+++ b/wp-includes/widgets/class-wp-widget-media-gallery.php
@@ -46,7 +46,7 @@ class WP_Widget_Media_Gallery extends WP_Widget_Media {
 	 * @return array Schema for properties.
 	 */
 	public function get_instance_schema() {
-		return array(
+		$schema = array(
 			'title' => array(
 				'type' => 'string',
 				'default' => '',
@@ -87,6 +87,11 @@ class WP_Widget_Media_Gallery extends WP_Widget_Media {
 				'should_preview_update' => false,
 			),
 		);
+
+		/** This filter is documented in wp-includes/widgets/class-wp-widget-media.php */
+		$schema = apply_filters( "widget_{$this->id_base}_instance_schema", $schema, $this );
+
+		return $schema;
 	}
 
 	/**
@@ -100,11 +105,11 @@ class WP_Widget_Media_Gallery extends WP_Widget_Media {
 	public function render_media( $instance ) {
 		$instance = array_merge( wp_list_pluck( $this->get_instance_schema(), 'default' ), $instance );
 
-		$shortcode_atts = array(
-			'ids'     => $instance['ids'],
-			'columns' => $instance['columns'],
-			'link'    => $instance['link_type'],
-			'size'    => $instance['size'],
+		$shortcode_atts = array_merge(
+			$instance,
+			array(
+				'link' => $instance['link_type'],
+			)
 		);
 
 		// @codeCoverageIgnoreStart
diff --git a/wp-includes/widgets/class-wp-widget-media.php b/wp-includes/widgets/class-wp-widget-media.php
index 4d190da360..ec412d25f7 100644
--- a/wp-includes/widgets/class-wp-widget-media.php
+++ b/wp-includes/widgets/class-wp-widget-media.php
@@ -127,7 +127,7 @@ abstract class WP_Widget_Media extends WP_Widget {
 	 * @return array Schema for properties.
 	 */
 	public function get_instance_schema() {
-		return array(
+		$schema = array(
 			'attachment_id' => array(
 				'type' => 'integer',
 				'default' => 0,
@@ -149,6 +149,18 @@ abstract class WP_Widget_Media extends WP_Widget {
 				'should_preview_update' => false,
 			),
 		);
+
+		/**
+		 * Filters the media widget instance schema to add additional properties.
+		 *
+		 * @since 4.9.0
+		 *
+		 * @param array           $schema Instance schema.
+		 * @param WP_Widget_Media $this   Widget object.
+		 */
+		$schema = apply_filters( "widget_{$this->id_base}_instance_schema", $schema, $this );
+
+		return $schema;
 	}
 
 	/**