Top SEO Tips for Optimising Images on your Website

If you use images on your website, then it’s just as important to work on their Search Engine Optimisation (SEO) as it is to work on the rest of your site. Like anything worth doing, this can take a little time, especially if you need to go through your site to optimise old images, but it’s well worth the effort.

By adding images to your site, you’re making it more visually appealing and therefore visitors are more likely to read it. At the same time, you’re adding chunky files that are likely to affect your site speed, so you need to ensure that your images are earning their keep on your website by playing a part in your overall SEO plan.

Why include images on your site?

Over 20% of web searches are Google image searches, which provides you with a lot more opportunities to reach out to your audience. If you’re not showing up on Google Images, you’re losing up to a 5th of your potential audience! Google is also getting smarter with image search, using advanced filters that help it identify relevant content and serve it to the right audience.

And for those who do visit your site, images make it more appealing and engaging. A website that has lots of text may have plenty of useful information, but that useful information becomes worthless if no one wants to read it.

It’s no good just popping an image or two in a blog though, and leaving it at that. Here are my top image SEO tips to help you rank well in search and drive more traffic.

1. Choose a suitable image

Although you should include images on your site, you don’t want to just use any old thing. Make sure it’s relevant to your content, complimenting and improving it.

Original images that you have taken or commissioned yourself are generally best. While stock photos can be handy – and you do get some very good ones – you don’t know where else they’ve been used and for what subjects. You don’t want to accidentally associate yourself with an undesirable site or company!

2. Name your file

Examples of good and bad SEO image filenamesToo often, images on websites have completely unrelated filenames. Before uploading to your site, pick a descriptive name. It should describe what’s in the image and use no more than four or five words separated by dashes (-). Although including keywords is good, don’t stuff the filename with them: an accurate description is more important.

3. Format, resize and compress your image

Size does matter. If your image is too heavy or large, then you’re going to seriously affect your page load time, and that’s bad news for your search engine rankings. You should resize and compress your image before you upload it to your site. Check the dimensions and file size, and resize them as appropriate for your use.

Even if you have a site like WordPress where images are automatically scaled once uploaded, you will still negatively affect your site speed with too-large images. The site will need to load the full (heavy) image and then reduce it’s size, all while the user is impatiently waiting for the page to load.

You can easily resize images on an image editing programme, or use one of the many online sites or WordPress plugins that are available.

When formatting, you also need to put some thought into the file type: .jpg, .gif, .png, etc. There’s no absolutely right answer for this and it will depend on your requirements. For example, .gif files are useful if you need a transparent background. Alternatively, .png images are generally better quality than .jpg, but they also create a larger file size. In most cases, you’ll probably find that a .jpg is high enough quality for a web page.

4. Use responsive images

Chances are that the majority of your website visitors will be browsing via their phone. Your SEO strategy and whole site design should prioritise mobile viewing, and that includes your images. Make sure that any images on your site automatically adjust depending on screen size.

If your mobile and desktop layouts utilise different framing, you should also ensure that any image you use looks correct in all instances. For example, if you have a face that looks fine on desktop, but is cut in half on mobile, then you need to rethink that image.

5. Add SEO-friendly alt tags

Once your image is uploaded, it’s time to make it as easy as possible for search engines to find and comprehend. First things first, you’ll want to add a descriptive alt tag.

An alt tag is what will be shown if your image doesn’t load. It’s also vital for site users with visual impairments, who can’t see the image and so need a description.

You should add alt text to every single image on your site – from a photo in a blog, to a header image, to your company logo. Again, you don’t want to stuff keywords, but you should definitely use target phrases while accurately describing what’s in the image. The alt text should also be in natural language, which means it makes sense to anyone (person or machine) reading it, rather than just a collection of words without structure.

Right: A cat in a hat sitting on a chair
Wrong: cat hat chair feline animal top hat moggy cut

If you display product images on your site, make sure you include the name of the product in your alt tag. A serial number here can also help Google identify the product.

6. File your images

The file path for your image – that is, where the image is stored on your site – is a ranking factor, too. Instead of uploading all your images to one generic Media file, create a structure of files that are more descriptive.

This is particularly useful for product images. If you sell clothes, for example, you could create folders for dresses, jeans, shorts, t-shirts… These could then be sorted into sub-folders such as cocktail dresses, summer dresses, formal dresses, and so on. This all gives search engines a little more information to help them serve the right information in searches.

7. Image Sitemap

A sitemap is vital for your website SEO, but most people think this relates only to pages. However, sitemaps are also important for image SEO. Not only does it help search engines find the images you use, it allows you to give an indication of which images you want them to index.

8. Structured data and schema markup

Image SEO - Google image search results for 'spaghetti'Structured data and schema markup help users and search engines identify the type of content an image relates to, therefore helping them to more easily pick the content they’re looking for. At the moment, Google supports four types of schema markup: products, recipes, videos, and GIFs. A small symbol in the bottom left corner of images in a Google search helps identify what the image relates to.

9. Lazy loading

No matter how well you optimise your images, they will still make up a good bulk of your website size and a bit of slow down with page load is inevitable. However, you can help mitigate this by utilising lazy loading.

Lazy loading delays the loading of images until they are needed. If you have a long page, the images that aren’t on the screen until you scroll down will load only when the user scrolls, rather than as soon as the page opens. This means that, instead of waiting for everything to load, the user is being shown content more quickly, and the rest of the page ‘catches up’ when it’s needed.


Search engine optimisation of your images is just as important as optimising the rest of your website content. Not only will it help your website look more appealing, it offers search engines more incentive to put your site in front of your target audience. From using the right file size to providing accurate descriptions, there is plenty you can do to optimise your images.

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