I would use the option [HTML escaped fields](https://community.denodo.com/docs/html/browse/6.0/vdp/administration/publication_of_web_services/publishing_rest_web_services/settings_tab_rest#html-escaping-the-data) present in Denodo to display the results in the form of Image in the Restful web service.
For this purpose, you can use any valid HTML statement having “img” tag that defines an image.
For example below is a valid statement that works fine:
<img src="https://upload.wikimedia.org/wikipedia/commons/f/ff/Wikipedia_logo_593.jpg" alt="Wikipedia" width="32" height="32">
Insert this value in a column of the table -> At design time, when defining the REST Web service, uncheck this field(By default all fields are selected) from the HTML escaped fields located in “Settings” Tab-> OK
Hope this helps!