Basically, you need to put a data view or template grid with the dynamic image viewer on your page. This dynamic image viewer needs an entity or a generalization of the system image entity. When creating your document make sure that you can reach this entity.
an example, with the image entity and a template grid, please use a generalization of the image entity for specifc images.
How to make an image entity - https://docs.mendix.com/refguide/image-viewer/
Info about the dynamic image in template – https://docs.mendix.com/refguide/dynamic-image-document-template/