Image SEO Guide: Optimize Images for Faster Pages

Images are often the heaviest part of a web page, and they are also a chance to be found in image search. Optimizing them improves speed, accessibility and visibility. Here is a practical checklist you can apply to any website.

Use descriptive file names

A name like red-sunset-over-beach.jpg tells people and search engines what the picture shows, while IMG_4021.jpg tells them nothing. Use lowercase words separated by hyphens.

Write useful alt text

Alt text describes the image for people who cannot see it and gives search engines extra context. Write a short, natural description of what is in the picture and avoid stuffing keywords. Purely decorative images can have an empty alt attribute.

Choose the right format and size

Use JPG for photos, PNG for graphics with sharp edges or transparency, and WebP when you want smaller files with wide support. Then resize each picture to the largest size it will actually be displayed at, using the Image Resizer. Our guide to JPG vs PNG vs WebP helps with the choice.

Compress for speed

Large images slow down the Largest Contentful Paint, one of the Core Web Vitals that measure page experience. Page speed is only one of many ranking signals, but faster pages are better for visitors. Run images through the Image Compressor at around 60 to 80% quality before uploading.

Set width and height

Adding width and height attributes lets the browser reserve space before the image loads, which prevents the page from jumping around. This helps the Cumulative Layout Shift score.

Lazy-load images below the fold

Lazy loading delays images that are not yet visible, so the first screen loads faster. WordPress adds this automatically to most images. Do not lazy-load the main image at the top of the page, because it needs to appear quickly.

Quick checklist

• Descriptive, hyphenated file name
• Helpful alt text
• Correct format for the content
• Resized to its display size
• Compressed to 60 to 80% quality
• Width and height set
• Below-the-fold images lazy-loaded

Frequently asked questions