Images and media files (directly)

Purpose

Clarify what Speed Layer does and does not do for images and media.

What Speed Layer can do

Help the browser fetch key images earlier

Speed Layer can influence fetch timing for resources that are likely to become important visual content, such as a hero image that becomes the LCP element. On repeat visits, it can add preload hints early in the page lifecycle.

Background:

MDN: link rel="preload" https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel/preload
Google: LCP https://web.dev/lcp/

What Speed Layer does not do

Speed Layer does not directly change media assets. It does not:

Compress images
Convert formats (for example, JPEG to WebP or AVIF)
Resize images
Re-encode video
Change your image CDN configuration

Those improvements require changes to image delivery, the CMS, or the CDN.

What to do if images are the main problem

If image weight is a major contributor to slow load times, common approaches include:

Using modern formats when supported (WebP, AVIF)
Serving responsive image sizes
Ensuring images have appropriate width and height attributes to reduce layout shift

Public references:

Google: Image optimization https://web.dev/fast/#optimize-your-images
MDN: Responsive images https://developer.mozilla.org/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images

How Speed Layer Helps Largest Contentful Paint (LCP)
What Is CLS (Cumulative Layout Shift)?
What Speed Layer Does and Does Not Do