Images Won't Show On Front Page

Hi!

I am using the Expound Theme at the following website: https://howtogetsixpackabsnow.siterubix.com/

I notice that the images that I included in the draft is not showing up on the front page when the post is published. However, the images are showing when you click on each post – for example:

https://howtogetsixpackabsnow.siterubix.com/getting-lean-body-fat-percentage-how-to-quickly-identify-your-body-fat-level

How can I fix this? Thanks.