CDN urls returned by graphQl are not webp as requested

Hydrogen and Storefront APIs
1

In a graphQl query, I ask for images like this:
thumbUrl: url(transform: {preferredContentType: WEBP, maxHeight: 200, maxWidth: 200})

This url is returned
https://cdn.shopify.com/s/files/1/0726/6012/3887/files/Mystic_Charcoal_Merino_2_200x200.png.webp
When inspecting the image from this url, it is a png. (98Kb)

If I remove .webp from the url, it weirdly returns a webp image (18Kb)
https://cdn.shopify.com/s/files/1/0726/6012/3887/files/Mystic_Charcoal_Merino_2_200x200.png

How can I get be sure to get webp?

Tested latest Chrome, latest macOS

2

Hi Torbjorn,

When you specify preferredContentType: WEBP in your GraphQL query, the CDN should ideally return a .webp image - so it sounds like you’re doing everything correctly. Is this happening for every image?

3

Weirdly, when testing again today. the images are returned as either webp or avif (even better). Sounds a lot like the ‘preferredContentType’ is ignored if Shopify gets an agent signature and can determine what image types my agent can process.