This is an accepted solution.
Hyde here from Shopify. Great question!
To ensure that your images are not pixellated or blurred, you would need to be uploading images that are of the right dimensions. As Empire is a third-party theme, they have their own documentation and guides for that here.
If that doesn't help, then their support is the best place to go. You can access their help by going to Online Store > Themes > Customize > Theme Settings and scrolling down to find their support.
I hope that helps!
All the best, Hyde.