Hi there,

The "QT: Testimonials" widget doesn't have an option for images.

If you would like to show testimonials with images there are 2 options:

1. SiteOrigin Editor

You can add testimonials by using a SiteOrigin Editor widget (please see attachment). 

Please note that you can't reproduce the default theme styled testimonials carousel with this step.

2. Plugin

You can download and install a plugin like Testimonial Builder which will add a new tab in the admin menu called "Testimonials" this plugin provide the option to display images within a testimonial.

Please note that you can't reproduce the default theme styled testimonials carousel with this plugin, due to this I recommend to go with the first option so you don't have to use an additional plugin.

Hope this helps.

You're welcome!