Every item in this checklist is something Google explicitly uses to understand, rank, or index your images.
Rename files before uploading. red-running-shoes-nike-air.webp signals relevance to Google. IMG_4892.jpg does not. Use hyphens, not underscores, between words.
Faster pages rank better. WebP is 25–35% smaller than JPG. Smaller images load faster, improving LCP — a direct ranking signal. Convert JPG to WebP free →
Target under 100 KB for hero images, under 60 KB for thumbnails. Use quality 75–82% for WebP photos — visually indistinguishable from originals at half the size. Compress images free →
Never serve a 4000×3000 image scaled down in CSS to 400×300. Resize first — it's a waste of bandwidth and a direct LCP penalty. Resize images free →
Alt text is Google's primary signal for what an image depicts. Be descriptive but concise: "A woman running in red Nike Air Max shoes on a trail" — not just "shoes" or "image". Decorative images (dividers, bullets) should have alt="".
Required to prevent Cumulative Layout Shift (CLS). Even if CSS overrides the dimensions, declaring them lets the browser reserve space before the image loads.
loading="lazy" for below-fold imagesNative lazy loading defers off-screen images. Don't apply it to the hero image — that's the LCP element and must load immediately.
Serve AVIF to browsers that support it, WebP to others, and JPG as universal fallback — without JavaScript.
Serve appropriately-sized images for each viewport. A mobile user on 4G should not download a 2000px image. Use srcset to offer 400w, 800w, and 1600w variants.
Google uses surrounding text to understand what an image is about. A photo of a product placed next to a descriptive paragraph about that product gets more context than a photo floating in an empty section.
Captions are often the most-read text on a page. They also give Google additional keyword context for the image. Include captions on editorial, news, and product images.
Check your robots.txt and CDN configuration. If images are blocked from crawling, they can't be indexed. Images loaded via JavaScript may also be missed — prefer server-rendered <img> tags.
Use Schema.org ImageObject to provide Google with image URL, dimensions, and license information. This is especially valuable for recipes, products, and news articles that show image thumbnails in search results.
EXIF data can contain GPS coordinates, camera serial numbers, and author information. Strip it before publishing. Remove EXIF data free →
An image sitemap helps Google discover images it might not find through crawling alone — especially images loaded dynamically. Include the <image:image> extension in your sitemap.xml.
Convert, compress, resize, and strip EXIF — all free, all in your browser.
⚡ Start OptimizingAlt text is a confirmed Google signal for image search. For web search, it provides context that can help the page rank for relevant queries, but it's not a primary page ranking factor — it's one of many.
There's no ideal number. Use as many as are genuinely useful to the reader. Each image is an indexing opportunity for image search, but large numbers of unoptimized images hurt page speed and therefore page rankings.
Yes, moderately. Google has confirmed that file names are a signal for understanding image content. A descriptive filename is a low-effort, high-value SEO step that takes seconds and has no downsides.