How can I remove the product thumbnails below the main product image?

You can hide the theme's thumbnails by following these steps:

  1. Sign into your Shopify admin
  2. Go to 'Online Store' > 'Theme'
  3. Click 'Actions' > 'Edit Code'
  4. Scroll to the 'Assets' folder and select the 'theme-custom.scss.liquid' file
  5. Paste in the following line of code:
    .secondary-images { display: none; }