On the Admin Portal, Click on the News link and select Publish News
In the Article Content Section click on the attachment icon as highlighted below.
Browse for the image on your device.
Repeat this process for more images remembering to put line spacing (Carriage Return) between each image.

Details on image sizing for articles here:
​http://help.clubzap.com/en/articles/2782515-what-size-images-can-i-add-for-news-articles