Skip to main content
All website issues
Speed

Images are too large for phone screens

What this means for your business

Images on your site are being served at full size even on small phone screens. A mobile visitor downloads a large desktop photo when a much smaller version would look identical — wasting their data and slowing your page.

How to fix it
Easy
30–60 minutes

  1. 1Your images are being served at a single large size regardless of the visitor's screen. A phone visitor gets the same image file as a desktop visitor — even though a much smaller version would look identical on their screen.
  2. 2Add the srcset attribute to your images to provide multiple size versions. The browser then chooses the right one automatically.
  3. 3Modern image hosting and CDN services handle responsive images for you — Cloudflare Images, Cloudinary (free tier available), and Imgix all resize and serve the optimal image for each device.
  4. 4For your most important images (hero images, product photos), create at least three versions: small (480px wide), medium (800px wide), and large (1200px wide). Reference all three in a srcset attribute.

On WordPress

WordPress automatically generates responsive image sizes when you upload photos — make sure your theme uses the built-in srcset support. Use the ShortPixel plugin to also compress each size automatically on upload.

On Shopify

Shopify handles responsive image sizing automatically when you use Liquid's {{ image | image_url: width: 800 | image_tag }} filter. If you're using raw <img> tags in custom code, switch to the Liquid filter and Shopify will serve the right size for each device.

Pro tip: Hero images are the biggest opportunity. A desktop hero image served to mobile visitors can be 5–10× larger than needed. Fixing just the hero image on your homepage often cuts 1–2 seconds from mobile load time.

Does your site have this problem?

SiteSprout scans your site, tells you which issues you actually have in plain English, and keeps watch so nothing breaks silently.

Scan your site free