Image SEO in 2027 for Beginners

Think of Google as a very fast reader who cannot see. It reads the text around a picture, the file name and the alt text, which is a short written description of the image. From those clues it decides what the picture shows and whether to include it in Google Images or next to a normal result.

Most beginners skip all of this. They upload a photo straight from the phone, accept a name like IMG_4821.JPG, leave the alt box empty and move on. The picture looks lovely to humans and says nothing to a crawler, which is the program Google uses to visit pages.

If you are brand new to the topic, my guide to what is SEO gives the wider picture first. For this post you only need one idea: every image on your site is a tiny page-within-a-page, and it needs a label.

First, accessibility. Alt text is what a screen reader says out loud when it reaches a picture. Google calls it the most important attribute for describing an image, so one good sentence helps a blind visitor and a search engine in the same stroke.

Second, speed. Google notes that images are often the largest part of a page. Heavy photos slow the page down, and slow pages frustrate visitors. My guide to Core Web Vitals on WordPress explains how the biggest image often decides your loading score.

Third, discovery. A picture can show up in Google Images, and some people go straight there to shop or compare. A bakery, a florist or a furniture shop gets extra chances to be found. Nobody can promise that your images will appear, but unlabeled images have little chance at all.

// the seven formats are BMP, GIF, JPEG, PNG, WebP, SVG and AVIF, per Google’s image best practices page.

Step 1: Use a Normal Image Tag

Google finds images in the src attribute of an img element, which is the standard way to put a picture in HTML. It does not index CSS background images. So if your theme shows a key product photo as a background, Google may never see it. Page builders sometimes do this, so check important pictures.

Step 2: Name the File Before You Upload

Google’s own example says my-new-black-kitten.jpg is better than IMG00023.JPG. Use plain words that describe the picture, separated by hyphens. Avoid generic names such as image1.jpg or pic.gif. If your site is in more than one language, translate the file names too.

Step 3: Choose a Supported Format

Google supports BMP, GIF, JPEG, PNG, WebP, SVG and AVIF. Photos usually work well as JPEG or WebP, simple graphics as PNG or SVG. Make sure the file extension matches the real file type, because a JPEG renamed to .png only confuses things.

Step 4: Write Honest Alt Text

Describe what the picture shows, the way you would to a friend on the phone. Keep it short and useful in context. Google warns against filling alt attributes with keywords. If the picture really does show a sourdough loaf and your keyword is sourdough bread, it will fit naturally. If not, leave the keyword out.

Step 5: Place the Image Near Relevant Text

Google says to put images near relevant text on a relevant page. A photo of a boiler repair belongs on the boiler repair page, next to the paragraph about it, not on the contact page.

Step 6: Keep the Same URL and Shrink the File

Reference an image by the same URL every time so Google can cache and reuse it. Then compress it before upload. High-quality pictures appeal to people more than blurry ones, so shrink the file size without making the picture look smeared.

Imagine a bakery in Leeds that sells sourdough online. The owner uploads a phone photo, and it arrives with these settings. Nothing is broken, but nothing helps either.

// example data, not a client result. File sizes depend on the photo and the compression you choose.

The owner then adds the sourdough page to the XML sitemap if images are loaded by script. Google recommends an image sitemap for pictures it might otherwise miss, and it allows image URLs from other domains, which helps if a CDN hosts them. If you are unsure how sitemaps work, see my guide to robots.txt and sitemaps.

// the first column is a made-up example. Writing a keyword list in alt text is the digital equivalent of shouting in a library: you get noticed, just not the way you hoped.

Open the page, right-click the picture, and choose Inspect. You should see an img element with a descriptive src and your alt text. Then paste the page address into the URL Inspection tool in Google Search Console and look at the rendered page. If the picture shows up there, Google can see it.

Next, look at the context. Google can pick a preferred image for a page from your structured data or from the og:image tag, and it advises against using a generic picture such as your site logo for this. My schema markup guide shows how to mark up the main image. Also keep the same alt text, file names and image URLs on mobile and desktop, as Google asks for in its mobile-first guidance.

Lastly, be patient. Google says changes can take anywhere from hours to several months to show, and suggests waiting a few weeks before judging. Do not rewrite 200 alt texts twice in one week because nothing moved on Tuesday.

How Long and How Much?

For a small site of 30 to 50 pictures, I would budget a few hours for a first clean-up, since each picture takes a minute or two. My rate is €25 an hour. If you want it done as part of a wider job, it sits inside on-page SEO, and my plans start at €475 a month. Compare with other cheap SEO services by asking what each one actually does, not just what it costs.

• Google Search Central: Image SEO best practices (formats, file names, alt text, sitemaps, CSS images)
• Google Search Central: SEO Starter Guide (alt text, images near text, how long changes take)
• Google Search Central: Mobile-first indexing best practices (same alt text and image URLs on mobile)

// last checked 11 Nov 2026. Example data is labeled as example data.