Which method is utilized for optimizing images in a Shopify theme?

The method that is primarily utilized for optimizing images in a Shopify theme is to utilize Shopify's image URLs and appropriate formats. Shopify automatically optimizes images upon upload, providing various sizes and formats which are tailored to ensure that images are delivered in the best way possible for different screen resolutions and devices. By leveraging these optimized image URLs, developers can ensure that the images load efficiently, contributing to faster page load times and an overall improved user experience.

Using only high-resolution images can lead to unnecessarily large file sizes, which may slow down loading times and negatively impact performance, especially on mobile devices. Compressing images without altering their formats is a good practice but does not leverage Shopify's built-in capabilities for image optimization, which includes serving the correct file type and size. Relying on customer uploads for images does not ensure that those images are optimized, as they may not meet the optimal size or format standards necessary for effective performance. Thus, utilizing Shopify’s image URLs and appropriate formats is the best practice for image optimization in a Shopify theme.