are these flag icons are expected to be on the dialog drop-down menu or on the HTML?
On the dialog, you can add a property "icon (String)" if you are using resourceType: granite/ui/components/coral/foundation/form/select
There was one article I remember, unfortunately it's throwing 404 for now. Please check this: https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/images-not-listing-in-the-...
Hope that helps!
For me also it's showing the same 404 error. Yeah i can refer that article but not working for me. Can you please tell me the way for AEM 6.5.