By PDS Team
Image SEO is the practice of making your images easy for search engines to find and understand, and fast for visitors to load. It covers alt text, file names, image formats, compression, sizing and where images sit on the page. Good image SEO can bring visitors from Google Images and helps your pages load faster, which improves the experience for everyone.
This guide follows Google’s image SEO best practices and turns them into a checklist you can apply to a business website.
Why does image SEO matter?
Optimised images can appear in Google Images and other search features, help Google understand your page, and make your site faster.
Product photos, project photos, infographics and diagrams can all bring visitors from image search. Images are also often the largest files on a page, so they have a big effect on Largest Contentful Paint (LCP), one of the Core Web Vitals. A heavy hero image can make a page feel slow even when everything else is light.
How should you write alt text?
Write alt text that describes the image accurately and briefly, in the context of the page, without stuffing keywords.
Alt text is read by screen readers for people who cannot see the image, and Google uses it, along with the page content, to understand what the image shows. Google’s guidelines recommend useful, information-rich alt text that uses keywords appropriately and fits the page context.
| Quality | Example alt text |
|---|---|
| Missing | (no alt attribute) |
| Too vague | “image” or “photo1” |
| Keyword-stuffed | “interior design Noida best interior designer Noida cheap interior Noida” |
| Good | “Modular kitchen with white cabinets and wooden worktop in a Noida apartment” |
Purely decorative images, such as background patterns or dividers, can use an empty alt attribute (alt=””) so screen readers skip them.
Do image file names matter?
Yes, descriptive file names give Google a small extra clue about what an image shows.
Google’s image guidelines say the file name can give clues about the subject of the image. “red-cotton-kurta-women.jpg” is more useful than “IMG_20240512_1032.jpg”. Use short, descriptive names with hyphens between words, and rename images before uploading them to your website.
Which image formats should you use?
Use a format Google supports and that suits the image: JPEG for photos, PNG for graphics needing transparency, WebP for smaller files and SVG for logos and icons.
- JPEG: good for photographs, with adjustable compression.
- PNG: good for screenshots and graphics with sharp edges or transparency, but files can be large.
- WebP: usually smaller than JPEG or PNG at similar quality, and supported by modern browsers.
- SVG: vector format for logos and icons that stays sharp at any size.
Google Search supports images in BMP, GIF, JPEG, PNG, WebP and SVG formats, according to its image SEO documentation. Many WordPress setups and image plugins can convert uploads to WebP automatically.
How do you make images load faster?
Resize images to the size they are shown, compress them, serve responsive versions and lazy-load images below the fold.
- Resize before uploading. Do not upload a 4000-pixel photo for a space that is 800 pixels wide.
- Compress. Use image compression tools or plugins to reduce file size without visible quality loss.
- Use responsive images. The srcset attribute lets the browser pick a smaller file on phones and a larger one on desktops.
- Lazy-load below-the-fold images. Add loading=”lazy” to images that are not visible when the page first loads.
- Do not lazy-load the main image. The hero or main product image is often the LCP element; load it straight away, and consider fetchpriority=”high” for it.
- Set width and height. Giving images dimensions prevents layout shifts as the page loads.
Image speed and responsiveness go hand in hand. Our guide to Interaction to Next Paint (INP) covers the JavaScript side of page performance.
How does Google find and understand your images?
Google finds images in standard HTML img elements on crawlable pages, and understands them using the surrounding text, alt text, titles and captions.
- Use regular <img> elements with a src attribute. Google’s guidelines note that it does not index CSS background images.
- Place images near relevant text, such as a product photo next to its description.
- Add captions where they help readers; text close to the image helps Google too.
- Make sure image URLs are not blocked by robots.txt if you want them in Google Images.
- Consider an image sitemap, or add images to your existing sitemap, especially for images loaded by JavaScript.
- Use structured data on product, recipe or article pages so images can appear in rich results.
An image SEO checklist for every upload
Run through these points each time you add an image to your website.
- Is it a real, relevant image (your own photo where possible)?
- Has it been resized and compressed?
- Is the format right (JPEG, PNG, WebP or SVG)?
- Does the file name describe the image?
- Is there accurate, useful alt text?
- Is it placed near relevant text on a crawlable page?
- Is lazy loading used only for images below the fold?
Our website design services build these practices into every template. For a full audit of image performance and indexing, see our technical SEO services.
Image SEO FAQs
What is the ideal length for alt text?
There is no fixed length in Google’s guidelines. Aim for a short sentence that describes the image clearly in the context of the page, usually a few words to around a line of text. If an image needs a longer explanation, such as a chart, describe it in the surrounding text instead.
Does Google read text inside images?
Google can extract some information from images, but it relies mainly on page text, alt text and other signals. Important information, such as prices, offers or contact details, should be written as real text on the page, not only inside an image. This also helps accessibility.
Is WebP good for SEO?
WebP is supported by Google Search and most modern browsers, and it usually produces smaller files than JPEG or PNG at similar quality. Smaller files help pages load faster. Use it where your website setup supports it, and keep a fallback for any old systems that need one.
Should I lazy-load all images?
No. Lazy-load images further down the page, but load the main image visible on screen straight away. Lazy-loading the hero or main product image can delay Largest Contentful Paint and make the page feel slower. Many site builders handle this automatically, but check your key templates.
Do image titles help SEO?
The title attribute shows as a tooltip in some browsers and is less important than alt text. Google lists the page title, captions, alt text and nearby text as helpful signals. Focus on accurate alt text, descriptive file names and relevant surrounding content first.
Can stock images hurt my SEO?
Stock images are not penalised, but they rarely help you stand out because the same images appear on many sites. Original photos of your products, team and projects show real experience and give Google Images unique content. Use stock only where you have no realistic alternative.
Want faster pages and better image visibility?
We optimise images and page speed for websites across Noida, Delhi NCR and India. See our technical SEO services or contact our team for a site review.
