Actually, it is not possible directly from News/Articles module.
Photo can be uploaded into Photos module and image manually inserted to TinyMCE area.

Images in Blogs can be used the same way, but Blogs have thumbnail image additionally - there is no post thumb in Articles/News.
Below is the legacy version of the Boonex site, maintained for Dolphin.Pro 7.x support.
The new Dolphin solution is powered by UNA Community Management System.