This news item is using the featured image (located at the bottom right hand side). It shows the green leaf.
If you have a picture you want to post with the news item (known as post), you can use the featured image. However, you can use the picture in a regular way by pressing Add Media at the top of the WYSIWYG. Than add the image like so.
Here is an example of using the image without feature image. Click the image and change its size by clicking on the pencil icon for editing. Currently, it is at medium size.