1. Go to Module builder and create a module
2. Add a field of type Related media > Images
3. Click Continue to finalize configuring the field
4. For Display selected items on the frontend using... select Custom from the dropdown
5. In the Type or Virtual path of the custom widget textbox enter the full type name of the Image gallery controller: Telerik.Sitefinity.Frontend.Media.Mvc.Controllers.ImageGalleryController, Telerik.Sitefinity.Frontend.Media
6. Click Done
7. Click Finish
8. Activate the module
9. Go and create at least one dynamic content item from the newly created type
10. Type the Title and select several images for Related images field
11. Go to Pages and create a page
12. D&D Sitefinity Dynamic content widget
13. View the page and go in the details of the item

Result:

Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.

Parser Error Message: Type 'Telerik.Sitefinity.Frontend.Media.Mvc.Controllers.ImageGalleryController' does not have a public property named 'Title'.

<sf:ImageGalleryController runat="server" Title="" UrlKeyPrefix=""  ProviderName="OpenAccessDataProvider" >
Line 19:                <RelatedDataDefinition RelatedFieldName="Avatar" RelatedItemType="Telerik.Sitefinity.DynamicTypes.Model.Pressreleases.PressRelease" RelationTypeToDisplay="Child" RelatedItemSource="DataItemContainer">
Line 20:                </RelatedDataDefinition>