Image SEO checklist for faster pages and better discovery

1. Give every important image a descriptive filename

Replace camera defaults such as IMG_4831.jpg with a concise name that identifies the subject, such as blue-running-shoe-side-view.webp. Use normal words separated by hyphens. Do not repeat keywords or force unrelated phrases into the name.

2. Write useful alternative text

Alt text should communicate the image’s purpose to someone who cannot see it. Describe what matters in the surrounding context. Decorative images should usually use empty alt text so assistive technology can skip them. Avoid beginning every description with “image of,” and do not copy the filename mechanically.

3. Build strong surrounding context

A relevant heading, caption, paragraph, and page title help systems understand why an image matters. An excellent image on a vague page is harder to classify than the same image placed beside specific, useful information. This contextual clarity also supports answer engines that extract concise explanations.

4. Reduce layout shifts

Include width and height attributes or define a stable aspect ratio. Reserving space prevents content from jumping while the image loads. This improves usability and supports page-experience metrics.

5. Serve the right size

Responsive image markup allows browsers to select an appropriate file for the screen. A phone should not download a huge desktop hero image. Compress each variant and use lazy loading for images that begin below the visible area, while allowing the main above-the-fold image to load promptly.

6. Choose a modern format with a fallback strategy

WebP is a practical default for many sites. AVIF can save additional bytes for some photographs. JPEG and PNG remain useful for compatible downloads, exact graphics, and established workflows. Test real content rather than assuming one format always wins.

7. Keep images crawlable

Do not block essential image URLs in robots rules. Use stable URLs, meaningful HTTP responses, and an image sitemap when a large catalog is difficult to discover through normal page links. Avoid requiring user interaction before the image URL exists in the page.

Complete image SEO checklist

• Descriptive, human-readable filename
• Context-appropriate alt text
• Relevant nearby copy and caption when useful
• Explicit width and height
• Compressed modern format
• Responsive sizes for different screens
• Lazy loading below the fold
• Crawlable URL and correct content type
• Consistent canonical page
• Testing with accessibility and performance tools