Image SEO

Image SEO refers to techniques that help search engines find, interpret, and display images. This includes using descriptive file names, writing relevant alt text, compressing images, serving responsive versions, and submitting image sitemaps. Proper image SEO can increase visibility in Google Images and support the hosting page's relevance.

Optimized images improve page speed, which is a ranking factor and part of Core Web Vitals. They also provide additional entry points via Google Images, which can drive traffic. Google uses page context, filenames, alt text, structured data, and crawlable image delivery to understand images. Original images tend to offer stronger topical relevance than stock photos.

Use descriptive, hyphenated file names that reflect the image content, such as 'red-apple-on-table.jpg' instead of 'IMG_1234.jpg'. Alt text should accurately describe the image for accessibility and relevance; avoid keyword stuffing. Alt text helps screen readers and search engines understand the image when it cannot be displayed.

Compress images to reduce file size without sacrificing quality. Use modern formats like WebP for better compression, JPEG for photos, PNG for graphics with transparency, and SVG for logos and icons. Tools like Squoosh or image optimization plugins can automate this process.

Serve responsive images using srcset and the <picture> element so the browser loads the appropriate size for the device. Always include width and height attributes to prevent layout shifts, which affect Cumulative Layout Shift (CLS), a Core Web Vital. Lazy loading can defer off-screen images but should be used carefully to avoid harming Largest Contentful Paint (LCP).

Submit an image sitemap to help Google discover images that might otherwise be missed. Use structured data, such as ImageObject schema, to provide additional context when the image is important to the page. This can enhance how images appear in search results.

Avoid generic file names like 'IMG_1234.jpg', keyword-stuffed alt text, and uploading oversized images that are only resized via CSS. Do not hide important images in CSS backgrounds or block image paths with robots.txt. Ensure images are crawlable by using standard <img> elements.

When uploading images: rename the file descriptively, write accurate alt text, resize to the maximum display size, compress the file, and choose the best format. Use a plugin for automatic compression and lazy loading. Submit an image sitemap and consider adding structured data for key images.