How to put a full screen image behind the testimonial slider

I’m using the Sydney testimonials slider and I would like to add a full width photo behind it. I place a photo behind it but it is cropped on the edges and I cannot seem to correct this. Perhaps, I need a different widget???

Hello there,

The background image of testimonial section in our demo is uploaded from Row Styles > Design. To make it full width, expand the Layout options, then enable Full Width on Row Layout dropdown.