Uploaded files and images have there own path, for example
http://localhost:8080/file?guid=1970324836974593
Some options can be used to get this in the html
The only option left is the
javascript snippet for mendix 8 widget https://marketplace.mendix.com/link/component/113004
But with that you use some extra javascript to add your html into the page. Not really elegant, but maybe the easiest for now.