Image Optimization for SEO: 12 Must-Know Tips

I’ve spent far too much time fussing over and changing images before settling on these 12 tips on image optimization for SEO.

Here’s something to think about, if a picture says a thousand words, why not optimize your images as you would for text on a webpage? Yes, you can optimize your images to help your website, articles, and images appear (higher) in search results.

The more content you create, the higher your chances of being found or having something take off. But that doesn’t mean you should be stingy on quality. Implementing a framework is one of the best ways to do this effectively.

This is the framework for creating optimized images that search engines love.

Image Seo Best Practices

12 Image SEO Best Practices

Follow these 12 best practices to ensure that the images you upload to your website work for you and not against you.

When it comes to SEO, it’s often the sum of all parts that can result in the most powerful results, so you shouldn’t rest on leaving your images unoptimized.

Here are 12 of the best image optimization tips for SEO that I can think of.

1. SEO-Friendly Alt Tags

Alt tags on your images describe what an image is and what it is for on your website pages.

These alt tags are used primarily for visually impaired site visitors; screen readers will be able to read the alt descriptions of your images and help the visitor better understand what your images are about and how they relate to your website or articles.

Search engines also crawl these alt tags, and by using search terms and phrases (which are relevant to the image and your articles), Google and other search engines can better index your images and help improve your website rank.

Alt Text Box On Wordpress

2. Resize Images Before Uploading

Cameras, smartphones, and stock image libraries have massive images. If you have a Sony A7III or Sony A6xxx camera, you’re creating 24MP images, which equates to about 6000 x 4000 pixels. These files can be 10-20mbs in size, and even the smaller images made by smartphones can be between 1-2mbs.

If you upload these photos and images directly to your website, whenever someone visits your article, their browser needs to fetch these massive files, which can drastically slow down your website speed.

Almost 50% of web visitors expect a website to load within 2 seconds, with 40% saying they will abandon a website if it doesn’t load within 3 seconds.

As most screens people view web pages on are 1080 or 1920 pixels wide (depending on whether they’re using a mobile or desktop device), and very rarely would you have an image that takes up the entire screen, you can easily reduce the size of your images to 1200 pixels in width.

An aspect ratio of 3:2 would result in an image with dimensions of 1200 x 800 pixels, which generally comes in around 100kb and loads much faster for site visitors.

A free online tool I use for image resizing is Befunky. Alternatively, if you want to add text and do some light editing, Canva is another free tool that will get the job done.

3. Optimize File Size

Reducing the dimensions of your images is not the only way to reduce your image file size so that pictures load faster on your website. Image compression and optimization are other ways to get that file size down to even smaller, and using tools like ShortPixel, you can even maintain the image quality.

There are other optimization tools for WordPress, like Optimizilla or other image optimization plugins, but I prefer ShortPixel. 

I’ve tested optimizing images with Optimizilla and then the image optimization plugin

I received the same image size compression with ShortPixel while maintaining much more image quality.

This also saves a lot of time, as I only have to upload the image to WordPress instead of first uploading it to Optimizilla, editing the file name, and then uploading it to WordPress.

ShortPixel comes with 100 free image optimizations per month (credits), but if you need more, their prepaid credit plans are very affordable and can be used on multiple sites. For example, you can get 50,000 image credits for a once-off fee of $29.99.

4. Correct Image Format

The correct format can save quite a lot of space; a JPEG file with a lot of detail saved in PNG format can be more than twice the size. The same can almost be said for simple graphics saved in JPEG format rather than PNG format. 

I have found that Portable Network Graphics (PNG) files are best for simple graphics where there aren’t any gradients, whereas JPEG images are better for photos and graphics that tend to have a lot of different image gradients.

PNG images are best if an image needs to have a transparent background, like many logos.

Try to avoid uploading GIFs as these can be quite large and slow down your pages, but if you want to include GIFs, reduce their dimensions as much as possible and remove the number of frames that are played, as this can drastically reduce the file size.

5. Convert To WebP or AVIF

WebP files can reduce the image size of your website pictures by a further 30%. This new image format is gaining popularity; now, most browsers support it.

To use the WebP format, the easiest option is to use an image optimization plugin like EWWW Image Optimizer or ShortPixel.

Using ShortPixel to convert your files from JPG or PNG to WebP will cost one credit for each converted image. If you don’t upload many images in your articles, this could be covered by the free 100 credits per month.

Otherwise, the one-time fee for an image package is quite reasonable.

AVIF format images are an even newer format of images that can reduce the file size of your JPEGs and PNGs by up to 50%. This format is gaining more popularity, and browsers are slowly starting to support it, but it’s not as popular as WebP images.

P.s. You can also use ShortPixel to convert your images to AVIF format.

6. Unique Graphics And Images

One thing that often goes unsaid regarding SEO optimization is using unique images in your posts.

Google crawls millions of stock images and can recognize when something is new and unique or when it’s just an image downloaded from a free stock photo library.

These stock images are also plastered across the web, and site visitors are far more likely to automatically skip past them as they’ve become accustomed to seeing them so often.

If you create or take your own images and use them to add value to your post, it will increase your visitors’ session time, and Google will recognize this new image as a possible resource for others in image searches. 

An example would be an image of a bicycle chain in use in an article about bicycle security.

Instead of using a random image, you can have an actual picture of the exact chain make and model in your image and use it.

7. Use an XML Sitemap

A sitemap tells search engines and their web crawlers what pages they should index and which are most important.

It would be best to use a sitemap for your website, and you can configure it for free with an SEO plugin like Yoast or RankMath.

Using Rank Math, you can enable the inclusion of your website images in sitemaps, which can help them get crawled more effectively by Google bots and other search engine crawlers.

8. Optimize File Names And Titles

Changing your file name from the generic name most images are given automatically, like “IMG_010721”, to something more relevant, like “Kryptonite New York Bike Lock,” can provide search engines with far more context to understand what an image is and to improve your overall SEO value.

When uploading your images and photos to WordPress, you’ll see that the file name is automatically added as the image title. 

Ensure that this title is also descriptive and keyword-rich to add some SEO strength to your pages where this image will be present.

Title Text Box On Wordpress

9. Use Relevant Images

Having an image of a person chasing a wild goose won’t have much context in an article about marketing strategy.

But if your text writes about doing marketing outreach without a clearly defined marketing strategy as a wild goose chase, where you’re just chasing dead ends, then you can see how the image helps emphasize the point and add relevance. 

Take it further and provide more context by adding labels to the person chasing the goose and the goose itself.

You may even have a shareable image that can generate backlinks when other marketers link to it from their articles.

10. Define Image Dimensions

Most WordPress themes and most website themes, in general, automatically define the size of images when you upload them, but if your website, for some reason, does not, then make sure to define them when uploading.

Undefined image dimensions are one of the major causes for Cumulative Layout Shift (CLS) on websites, which can cause your website to fail Google’s Core Web Vitals, which since June 2021 has been a ranking factor for websites.

What happens when your image dimensions aren’t defined is that when you open the page, the image has not yet loaded; as soon as the image does load, however, the content below the image is shifted down, which creates a bad visitor experience and negatively affects your SEO performance.

When the image dimensions are defined, the space on your webpage where the image should go is “reserved,” so even though the image may not load immediately when someone opens the website, space will be there and filled with the image once it loads and no content on the page will shift around.

11. Mobile Responsiveness

Most themes on WordPress these days are mobile responsive, and the images they display are also. This means that when someone visits your website on a device with different screen sizes, like a smartphone or tablet, the website’s content fits the screen, no matter what device they use.

For images, this means that the image size will scale based on the display resolution of the device (or frame). So you’ll see an image that fits the screen properly, whether you’re viewing it from a smartphone, tablet, or smart TV.

If your site is not mobile responsive, you can make the changes yourself, but I highly recommend switching to a responsive theme as the easiest, safest, and fastest option.

12. Minimum 1200 px for Discover

Google Discover can be a great way to promote your blog for free (and on autopilot), especially when covering trending and shareable content.

But there are some rules you need to follow to get shown on Google Discover. One of these eligibility factors is related to the minimum size of your images. You need images at least 1200 px wide for them to appear in Discover.

Also, ensure your WordPress media settings are not on the default max setting of 1024 px. Head to your WordPress Dashboard > Settings > Media, and then change the width of the large image setting to at least 1200 px.

Final Thoughts

As you can see, it just takes a few small changes to how you create content to produce SEO-friendly images for your website. By following the framework in this article, you’ll only have to tweak your workflow a little to make a massive change. 

And with the addition of a few tools, you can optimize your pictures almost on autopilot.

Now that you know these 12 images SEO best practices, you can start implementing them on your website or blog, and in the coming weeks and months, start to see your articles and images rise in the rankings.

Have you been optimizing your images? What type of speed differences have you seen?

David Woutersen

Article by

David Woutersen

David is the founder of and has been in the social media industry since 2017. Since then, his mission has been to help others take control of their online presence. For some, this has been earning an income online; for others, it's teaching how to use social networks more effectively. And each year, he continues to help millions with strategy, troubleshooting, and inspiration.

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