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How to optimise images for SEO

Have you ever checked how much traffic your website receives from Google’s image search feature? Traffic from image search might not seem particularly valuable, but it’s an easy SEO win that can increase your website’s visibility and effectiveness.

Compared to keyword search, image search generates only a small fraction of total Google search traffic – according to, about 0.5%. Despite this, it’s an easy traffic source to optimise for that can have a real effect on your bottom line.

Image search is less competitive than keyword search, with fewer SEOs competing for high-traffic keywords. This lack of competition makes achieving broad rankings that bring in large amounts of traffic far easier than it is for keyword search.

While image search should never be the biggest pillar of your SEO campaign, it’s an excellent source of traffic that’s easy to optimise for. Compressing the size of your images also reduces page load times, which leads to higher rankings in normal web search, too.

In this blog post, we’ll share six best practices to help you optimise your website’s images for better rankings.

Use descriptive filenames

If you’re uploading an image to your website from your smartphone, digital camera or scanner, it probably has a numerical filename, typically beginning with DSC, that was automatically generated by the camera that captured it. This type of filename is great for sorting images by date on a memory stick, but it’s completely useless to search engines. Since search engines can’t see your pictures, they use elements like their filenames to work out what content they contain. Use descriptive filenames for your images that clearly explain what the image is all about. Your image’s filename should be a short (five words, at most) description of exactly what it features. For example, an image of a pair of men’s black leather shoes should have a filename of “mens-black-leather-shoes.jpg” or similar. A short but descriptive filename acts as an indicator of your image’s content for search engines.

Don’t forget image alt text

Alt text is a description of your image that search engines use to determine what it contains. The biggest difference between an image’s alt text and its filename is that alt text is much more detailed.

While your image’s filename should describe what it is, your image’s alt text should be a description of what your image’s content is as you would explain it in a complete sentence.

Let’s go back to our men’s black leather shoes example above. Our image’s filename is “mens-black-leather-shoes.jpg”, while our alt text is “A pair of men’s black leather shoes”.

Like your image’s filename, the alt text you use to describe an image should include your primary search keyword. Try to write a short but detailed alt description that naturally includes your target keyword without resorting to keyword stuffing.

Use large, lightweight images

The bigger your image, the better. Since most monitors have a resolution of at least 1366 x 768, you’ll want to ensure your image is able to take up the entire display on most computer monitors. As long as your image is reasonably sized, it won’t suffer from any disadvantages in Google image search. Try to avoid using small, thumbnail-sized images unless they are the only option that’s available. As well as being large enough to be visible on most monitors, it’s important that all of your images are lightweight. Large images take longer to load and are less likely to rank highly in Google’s search results.

Amazon found that if their pages slow down by 1 second, they lose $1.6 billion a year.

Use software like Adobe Photoshop or Skitch to make sure your images aren’t too large. Use file formats like JPG and PNG, which are far more compact than GIF and TIFF, and aim for an average file size of less than one megabyte per image.

Image Source - Shopify

Image Source – Shopify


Create link-worthy images

Links don’t just matter for websites – they’re also hugely important for images. The images that rank most prominently in Google image search are usually images that are linked to by other websites. If you’re creating images manually to use in your website, make sure that they’re of a high quality level. Images and infographic that are insightful and detailed are more likely to be linked to from forums, blogs, online communities and other websites. Just like anchor text determines the keywords your webpages will rank for, anchor text has an effect on image rankings. If you’re building links to your images, use an accurate, relevant anchor text that matches your image’s content.

Use images in rich snippets

Images aren’t just useful for increasing the amount of traffic your website gets from Google image search. Images that are related to your page’s content can be added to rich snippets, increasing your website’s clickthrough rate from the search results.

Rich snippets are detailed snippets of your website’s content that appear in Google’s search results. Using rich snippets, you can make page elements such as images, star rankings and track lists appear in Google’s description of your website.

You can learn more about rich snippets in Google’s Webmaster Tools support. When used correctly, rich snippets can result in a significant increase in your clickthrough rate from Google search.

Use images that match your content

If you use unrelated or misleading images in your content – for example, a picture of a celebrity in a blog post about accounting – you’ll generate traffic that’s completely worthless and uninterested in your products or services.

This might be alright if your website is monetised using CPM ads, but it’s a waste of time if you offer a product or service. As such, you should only use images that add to your page’s value and match the rest of the content on your website.

Choose images that complement or match your content and you won’t just get traffic from Google image search – you’ll get new readers, subscribers, lead and customers that help your business grow.

Are your images optimised for SEO?

Does your website use images that are optimised for Google search, or do most of your images still have numerical filenames and no alt text? Optimising your site’s images takes very little time and pays dividends in traffic, leads and sales.

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