Image SEO: How to Get Traffic From Google Images

When people plan their SEO, they think about keywords, headings and backlinks — and forget that Google runs a second search engine most of them never optimise for. Google Images drives clicks for recipes, products, tutorials, travel, crafts, interiors — any topic where people decide with their eyes. Because so few sites do the basics properly, image search is one of the last places where careful, boring technical work still beats bigger competitors. This guide covers those basics, in the order they matter.

Start with the filename

Google reads your filename before it renders a single pixel. IMG_4032.jpg tells it nothing; chocolate-cake-recipe.jpg tells it exactly what the image shows and which queries it might satisfy. The rules are simple:

• Describe the content in three to six words: blue-linen-summer-dress.jpg, not product-final-v2.jpg.
• Use hyphens between words, all lowercase. Underscores and spaces cause parsing quirks; hyphens are the convention Google documents.
• Rename before uploading. Most CMSs keep the original filename in the URL forever, and changing it later breaks the image's indexing history.

It takes five seconds per image and it is the cheapest ranking signal you will ever set.

Alt text: describe for humans first

Alt text exists for people using screen readers and for anyone whose connection fails to load the image. Google uses it as a ranking signal precisely because it is meant to be an honest description — so write it as one. If your alt text reads naturally aloud, it is almost certainly good SEO. If it reads like a keyword list, it is spam, and Google treats it accordingly.

One sentence, under about 125 characters, no "image of" or "picture of" — the screen reader already announces that it is an image.

File size: images are a Core Web Vitals problem

Image search rankings inherit your page's health, and images are usually the heaviest thing on the page. An oversized hero image is the single most common cause of a poor Largest Contentful Paint score, and LCP is part of Core Web Vitals — which feed into ranking for both web and image results. The fix is mechanical: resize to the display size you actually need, compress photographs as JPG or WebP, and lazy-load everything below the fold. Our full walkthrough is in How to Optimize Images for a Faster Website; as a rough target, a content photo should land under 200 KB and almost never above 500 KB.

Format choice matters here too. Photographs belong in JPG or WebP; screenshots and graphics with text belong in PNG. If you are unsure which is which, the PNG vs JPG guide settles it in two seconds.

Dimensions and responsive images

Serve images at sensible dimensions and tell the browser about them. Upload a version wide enough for your largest layout (around 1200–1600 px for most content sites — not the 6000 px original from your camera), always set the width and height attributes so the browser reserves space and the page does not jump while loading, and where your CMS supports it, use srcset to offer two or three sizes so phones download a 600 px file instead of a 1600 px one. Google can discover every variant you list and typically surfaces a high-resolution one, users get the smallest file they need, and your layout-shift score improves as a side effect. If you need to produce those size variants, our free Image Resizer does it in the browser — your photos never leave your device.

Captions and surrounding text

Google reads the neighbourhood, not just the image. The caption, the paragraph before and after, the nearest heading and the page title all tell it what the image is about — and captions are among the most-read text on a page: skimmers who skip paragraphs still read them. A relevant image placed next to relevant text ranks; the same image dumped in an unrelated sidebar does not. Practical consequence: put your most important image near the top of the page, close to the heading that names your topic, with a caption that adds information rather than repeating the alt text.

Image sitemaps, briefly

An image sitemap (or image entries inside your regular XML sitemap) lists the images on each page so Google can discover ones it might miss — especially images loaded by JavaScript or galleries. Most SEO plugins generate these automatically; if yours does, you are done. Building one by hand is only worth it for large image-driven sites. It helps discovery, not ranking — a sitemap gets an image found, everything else in this guide gets it chosen.

Original images beat stock — every time

Google can recognise when the same stock photo appears on thousands of sites, and it has little reason to surface your copy above the other ten thousand. An original photo — even an imperfect one taken on a phone — is unique to you, so any image search that matches it can only lead to your page. Originals also earn clicks in ways stock cannot: they look like real information rather than decoration. If you publish originals you care about, consider a light watermark; our watermarking strategy guide covers how to protect images without ruining them.

Structured data: the shortcut for products and recipes

If your pages describe products, recipes or how-tos, add the matching schema.org structured data (Product, Recipe, HowTo) and reference your images inside it. This is what makes Google show your image as a rich result — a recipe card with a photo, a product with a price badge — which earns dramatically more clicks than a plain thumbnail. For everyone else, structured data is optional polish; for these three content types, it is the highest-leverage item on this page.

The 7-point image SEO checklist

Run new posts through this list and fix old posts opportunistically, starting with the pages that already get some search traffic — they have the shortest path to more.

The bottom line

Image SEO is not a trick; it is a habit of labelling and serving images properly. Name the file, describe it honestly, keep it light, size it responsively, surround it with relevant words, prefer your own photos, and mark up the pages where rich results exist. None of it is glamorous — which is exactly why the sites that do it keep quietly collecting visitors from a search engine their competitors ignore.