Which Liquid filter would you use to go from URLs to images?

The img_url filter is designed to convert URLs into appropriate image tags within the Shopify platform. This filter works specifically with Shopify's content delivery network, allowing for the transformation of a URL that points to an image file into an HTML image element. When the img_url filter is applied, it generates the correct image sizing and format, optimized for display within the storefront.

Using this filter simplifies the process of rendering images in a Shopify theme by ensuring that the appropriate paths and sizes for images are utilized, following the best practices for speed and performance. It effectively takes a generic URL that points to an image and ensures it can be displayed as an image element in a responsive manner.

The other options focus on more specific scenarios, such as particular image types related to product or variant images. While these filters are useful in their contexts, they wouldn't apply universally to all URLs pointing to images as the img_url filter does. This makes the img_url filter the most versatile choice for converting URLs to images, thereby solidifying its position as the correct answer.