Switching from two columns to one

I’ve recently started a wordpress blog. I’m using the following theme: https://www.bluchic.com/support/knowledgebase.php?category=17

I wrote a post in which I wanted my photos to show in two columns. All I did was click on the two column icon on the top of my page. Since then, all of my new posts are showing in two columns. I’ve tried everything but I can’t get them to show in one column. The support guy for the people wo created the theme said to unclick the two column box under the General Settings tab. That box was never clicked. I went back and double checked. I have no clue how to fix this problem. Any help would be very much appreciated!