Unable to update photos to home page

I suspect this is a stupid newbie question.

I had HighEnd installed for me by Mojo Marketplace. The service included having the them installed to look like the demo.

I thought I’d be able to replace the photos on the home page with my own. After days of trying to figure out why I’m not able to, it has finally dawned on me that having the demo theme is probably the problem.

Is this true? If so, how can I go back the version of the theme that lets me put my own product photos on the front page?

Also, I had WooCommerce added by Mojo. My Dashboard says this: “Your theme has bundled outdated copies of WooCommerce template files. If you notice an issue on your site, this could be the reason. Please contact your theme developer for further assistance.”
Could you help me with this or tell me who could?

Thank you