To use RokMiniNews, you first need to drag the widget into the widget position Newsflash and then set the category dropdown, to the category that you would like to use with RokMiniNews.
To add image to the RokMiniNews post, you have to edit the field : Images in RocketTheme Extensions below your post edit area or add a Custom Field in the table below the post edit box. From the list please choose (or add new field) ‘image’ and fill the field under Value with your path to the image ie. http://your-site.com/wp-content/uploads/2009/09/image.jpg
To check the path to an image, please go to the Media page in your administration dashboard, click Edit under the image you wish to use, and copy the path from the File URL field.