Hi Niks. The nice thing about Lighthouse Studio (formerly SSI Web) is that you can go into Survey Settings > General Format and use your own graphics as radio buttons, checkboxes, and previous and next buttons. I prefer to use SVG (scalable vector graphics) for these images because they scale and look good on any device, regardless of size.
We added three new survey styles (Archivo, Lato, and Lora) to Lighthouse Studio 9 that come with those graphic types pre-loaded via their stylesheets, but you can use SVG graphics in previous versions even though it isn't a supported file type in the software dialogs--you simply specify the complete filename with its extension; i.e. graphic.svg.
Here is a link to the SVG graphics used in these new styles.