Hi there @Firefly1,
Yes, it's possible. Would you mind sharing your store URL? I need to take a look before I can offer any suggestions.
Thanks for reaching out.
I appreciate that you have included the link to your store. You can make slight changes to the size of the slideshow within the Theme Editor. You can open the Theme Editor by navigating to Online Store > Customize, I took a screenshot of my test store to show you the section I am referring to:
Within the Theme Editor, you can select on the slideshow section to make changes to the slideshow height.
I can definitely see how allowing you to make changes to the width of the slideshow would be beneficial for customizing your store. One thing I can do is send your request up to our development team for you.
Alternatively, since you are using the Debut theme which is designed and supported by Shopify. You can use free Design time with Shopify themes to have our internal themes team make the corresponding changes to the coding on your behalf. If you are interested in using design time for your theme, you can reach out to a Shopify Advisor by logging into your store through our Contact Us page.
Let me know what you think.