Image Optimization for SEO: 11 Must-Know Tips

I’ve spent far too much time fussing over and changing images before settling on these 11 must-know 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 your images themselves appear (higher) in search results. 

I believe in the principle that the more content you create, the higher your chances are of being found or having something take off. But that doesn’t mean you should be stingy on quality. One of the best ways to do this effectively is to implement a framework.

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

11 Must-Know Tips To Optimize Your Images For Search Engines

Follow these 11 tips to ensure that the images you upload to your website are working 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, which is why you shouldn’t rest on leaving your images unoptimized.

Here are 11 of the best image optimization for SEO tips I can think of.

1. Use 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 it relates 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.

2. Resize your 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 in size.

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 1000 pixels in width. An aspect ratio of 4:3 would then result in an image with dimensions of 1000 x 750 pixels, which generally comes in around 100-200kbs in size and loads much faster for site visitors.

A free online tool I look to 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.

Image Optimization - 11 Must-Know tips for SEO
Made with Canva

3. Compress and optimize image file size

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

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

Having tested optimizing images first with Optimizilla and then the image optimization plugin reSmush.it, I received the same image size compression with ShortPixel while maintaining much more of the 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. Upload files in the correct file 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 amount of frames that are played as this can drastically reduce the file size.

5. Convert uploaded JPGs and PNGs to WebP or AVIF format

WebP files can reduce the image size of your website pictures by a further 30%. This new image format is gaining popularity and 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.

If you use ShortPixel to convert your files from JPG or PNG to WebP, it will cost 1 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 quite as popular as WebP images just yet.

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

6. Use unique images and photos

One thing that often goes unsaid when it comes to image optimization for SEO is to use 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 just automatically skip past the image as they’ve become accustomed to seeing these images so often. If you create or take your own images and use them in a way that adds value to your post, it’s going to increase the session time of your visitors, and Google will recognize this new image as a possible resource for others in image searches. 

An example of this 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 in use.

7. Use a sitemap so your images are crawled more effectively

A sitemap tells search engines and their web crawlers what pages they should index and which ones are most important. You should definitely use a sitemap for your website, and you can configure them for free with an SEO plugin like Yoast or Rank Math.

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

8. Optimize file names and image 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. Make sure that this title is also descriptive and keyword-rich to add some SEO strength to your pages where this image will be present.

9. Make your images relevant to the text

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 is like 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 a step further and provide even more context by adding labels to the person chasing the goose and the goose itself and you may even have a shareable image that can even generate backlinks for you when other marketers link to it from their articles. 

Doing outreach without a marketing plan meme

10. Define your 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, is 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. Make sure your images are mobile responsive

Most themes on WordPress these days are mobile responsive and the images they display as well. What this means is that when someone visits your website on a device with different screen sizes, like a smartphone or tablet, the content of the website fits the screen, no matter what type of device they are using.

For images, this means that the image size will scale based on the size of the device. So you’ll see an image that fits the screen properly no matter if 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.

Final Thoughts on Image Optimization for SEO

As you can see, it just takes a few small changes to the way you create content to produce SEO-friendly images for your website. By following the framework laid out in this article, you’ll only have to tweak your workflow a little, in order 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 11 image optimization tips to boost your SEO value, you can start implementing them to your website or blog and in the coming weeks and months start to see your articles and images rise in the rankings.

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Hi Frank.