Top SEO Tips for Optimising Images on your Website

If you use images on your website (and you should), then they need optimised for search, just like every other part 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 including images to your site, you make it more visually appealing, so visitors are more likely to stay for longer. On the flip side, image files tend to be chunky and can greatly affect load speed. That being said, you need to ensure that your images earn their keep by boosting your overall SEO strategy.

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Why include images on your site?

Over 20% of web searches are Google image searches. 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, images make your site 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. For the vast majority of users, blocks of text need to be broken up to be more readable, and imagery is a great way of doing this.

It’s no good just popping an image or two in a blog though and leaving it at that. You need to make sure images are fully optimised for search, accessibility, and page speed.

Here are my top SEO tips to help your images and overall site rank well in search and drive more traffic.

Easy steps for optimising images on your website

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 they’re relevant to your content, complimenting it and improving it.

Original images that you have taken or commissioned yourself are generally best. They’re more personal to your business, can complement your branding, and elicit a higher level of trust amongst users.

Stock photos, on the other hand, are much more budget- friendly and readily available.

If you can afford your own unique imagery, use that. But high-quality stock imagery is a perfectly acceptable alternative for SEO if you’re tight on funds and can find something suitable.

2. Name your file

Examples of good and bad SEO image filenames

Too often, images on websites have completely undescriptive filenames, or filenames that are unreadable. 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 (-).

Including keywords is good, but don’t stuff the filename with them: an accurate description is more important.

3. Resize and compress your image

Size does matter. If your image is too heavy or large, it can seriously affect page load time, and that’s bad news for your search engine rankings. Resize and compress images before uploading them. Check the dimensions and file size, and resize them as appropriate for your use. 

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

You can download simple software to your computer for editing images, or use free online tools such as TinyJPG and Birme.

4. File format

Put some thought into the type of file you use: .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, a .jpg is high enough quality for a web page and should be your go-to file format.

5. Use responsive images

Chances are that the majority of your website visitors will browse 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 based on screen size.

If your mobile and desktop layouts utilise different framing, you should also ensure that any image you use looks correct on all devices. 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.

6. Add SEO-friendly alt tags

Alt text on an image

An alt tag is a description of an image, which is usually hidden in most viewing experiences, but which will be shown if your image doesn’t load. It’s vital for site users with visual impairments who can’t see the image and so need a description. Alt tags are also useful for SEO because they help search engines better understand page content.

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 shouldn’t stuff keywords into these descriptions, but it’s advantageous to use keywords if you can do so while accurately describing the image. 

Alt text should be written 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, which can improve search.

7. File your images

The file path for your image – that is, where the image is stored on your site – is a ranking factor. 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 gives search engines a little more information to help them serve the right content in search.

Intermediate steps for optimising images

The following steps are more advanced methods for optimising images for search. If you use WordPress, many of these can be easily implemented with the help of plugins such as Yoast. However, if you use another platform, you may have to get the help of a developer or edit code yourself (but only if you understand what you’re doing).

8. Image sitemap

A sitemap is vital for your website SEO, but most people think this relates only to pages. However, a sitemap is also important for image SEO. Not only does it help search engines find images across your site, it allows you to indicate which images you want to be indexed (i.e. displayed on Google).

Many website builders nowadays will automatically generate a sitemap. If your site is built on WordPress, you can add one for free using the Yoast plugin

If you’re not sure whether you have a sitemap, enter one of the below common sitemap URLs (replacying with your actual website name):

  • com/sitemap.xml
  • com/sitemap_index.xml
  • com/sitemap/

If you have an image sitemap, you should see a link to it on here. If not, you can easily create one with tools such as My Sitemap Generator. You will need to know how to upload the results to your website, or else ask a developer to help you.

9. Structured data and schema markup

Image SEO - Google image search results for 'spaghetti'

Shema markup – also referred to as structured data – helps users and search engines identify the type of content an image relates to, and provides further information on that image. Plugins like Yoast can automatically add Schema markup, otherwise you will need to edit the code.

You can add structured data to individual images, which is particularly useful if you want to share details such as licensing, copywriter and creator. Alternatively, images can be included in Schema for other elements of your page. For example, if you markup a recipe with Schema, you can add a link to an image of the finished piece.

Schema markup is a complete topic on its own, so I would recommend focusing on other elements of image optimisation first. Or you can read more about it in Google’s guidance.

10. Lazy loading

No matter how well your images are optimised, they will still make up a large proportion of your website size. As a result, some reduction in page load speed 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, images will only load as they are viewed on a device. Images not yet on the screen will only load when they become visible. This means that, instead of waiting for everything to load, the user is 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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