Add max resolution for the Image editor in Grid Layouts to avoid performance hit when using high res images.

src/Umbraco.Web.UI.Client/src/views/propertyeditors/grid/editors/media.html

@@ -9,7 +9,7 @@
 		<img
 			ng-if="url"
 			ng-click="setImage()"
-			ng-src="{{url}}"
+			ng-src="{{url}}?width=800&upscale=false"
 			class="fullSizeImage" />
         <input type="text" class="caption" ng-model="control.value.caption" localize="placeholder" placeholder="@grid_placeholderImageCaption" />
  	</div>