Image optimization is a critical aspect of SEO, but it's often overlooked.
Many digital marketers will optimize image alt tags and think they're ticking the box of image SEO. But in reality, there's much more involved if you want to get your images ranked high and use them to drive traffic to your site.
Optimizing images should form part of your ongoing SEO strategy and be treated as a best practice you should follow for all your images.
Because SEO rules are evolving constantly, the challenge for marketers is knowing where to spend their time in order to get the best return on image SEO.
In this article, we'll cover the most important topics:
What is Image SEO?
Image SEO is how you optimize your images to rank them higher in Google Images and across search engines as a whole.
Image SEO involves lots of strategies, from ensuring your image quality is high and images load quickly, through to on-page optimization, optimizing image titles and adding image alt tags.
All of these things help give your content a boost in search results pages and Google Image search results, ultimately making your site more discoverable, increasing traffic and improving user engagement.
Why should you care about Image SEO?
Visual search is increasingly important.
Just look at the evidence:
Image search represents about 30% of all queries generated across the top 10 US web search properties, according to Moz.
Daily pageviews of Google Images is greater than one billion, according to Benjamin Ling, Director of Search Products at Google - and that figure was shared ten years ago. So you can take an educated guess that this would be way higher today. Especially if you look at the rise of visual social media- there are more than 600 million searches on Pinterest every single month.
In short, image SEO really matters.
Take a look at the advantages of image SEO for businesses:
1. Optimized images drive quality organic image search traffic
With high quality, optimized images, you can drive significant amounts of traffic to your site.
Not only do high quality images make your web pages and content look better, but they actually help drive traffic from search engines in the first place:
Images are returned by Google for 34% of search results, according to Econsultancy.
2. Images increase engagement and time on page
First, images encourage people to click on your posts.
If people have to choose between a post on Facebook or Pinterest, they're going to click on the one with the image that's most compelling to them - and that will impact the search ranking of your content in the long run.
With good quality, optimized images, those visitors will then spend more time on your website and be more engaged with your content.
Content with optimized images actually increases user engagement by 90%, according to Buffer.
Anything that improves user experience and engagement on your website is good news for your SEO performance.
Optimizing images is especially important for eCommerce stores to provide a clear and engaging catalog of products, and help improve sales.
3. Images help drive backlink opportunities
Backlinks are SEO currency. You can almost always use more backlinks to boost your search rankings, but it can be challenging to find new ways to get fresh backlinks.
This is where images can really help.
Creating high-quality original images is a fantastic opportunity to earn backlinks because other websites will want to use your image for their own pages. Let's say you create an incredible infographic for your industry, chances are other sites will want to share it on their sites with links back to your business.
This means your images can have a direct impact on the amount of traffic, leads, and conversions you get for your business.
The best way to generate backlink opportunities is to create something that people are interested in - something that revolves around and resolves customer pain points, or shares facts, how-to's, tips, and quotes.
4. Optimized images help improve page load speeds
Images can have a huge impact on page loading speeds. And loading times are incredibly important for user experience and SEO.
The faster a site, the easier it is for search engines to crawl and index your pages. Google even prioritizes faster sites, optimizing your images can help you rank higher on search results and attract more visitors.
And once they're on the site, visitors get a better experience and are more likely to stick around.
5. Optimized images improve site accessibility
If people are using screen readers due to any visual impairment, optimizing your images ensures that no information gets lost in these situations.
At the same time, it means your site provides the best possible user experience for all users.
6. Creating unique images
Google and users prioritize original content. So, if you want your images to rank on image results pages, and you want users to engage with your content, it's vital you use original, unique images.
The first image of your page must be eye-catching and original. Choosing the right image upfront can capture visitors' attention and significantly decrease your page bounce rate, which is important for SEO.
When visitors see a great image upfront, they are more likely to keep scrolling. But if they are seeing the same image on lots of sites and pages, they will quickly lose interest.
This is especially important for eCommerce websites, as product images can do most of the selling for you.
Many consumers use images to shop for goods - 50% of online shoppers say images helped them decide what to buy.
Consider using tools like Canva to design in-house graphics and investing in great product photography for your site - the ROI will be worth it.
What influences your images' ranking?
To understand what you need to do to optimize your images, it's important to know what influences image ranking.
Discoverability, crawlability, indexability
To provide the most relevant and useful search results, Google does three things:
Crawl: Crawlers are sent out to scour the internet for content. They look through the code and content of each URL, including text, image, video, or any other format.
Index: The content found is organized into the index, and these indexed pages can then be accessed quickly by Google when a user types a search query.
Rank: Google uses a ranking algorithm to weigh up the quality and relevance of pages according to what users are searching for. The results are then ordered on the search engine results pages according to relevance.
In order to ensure your images show up in search results, the first step is to ensure search engines can crawl and index them by creating an image sitemap or make sure your images are featured in your sitemap.
What is an Image Sitemap?
A sitemap is an XML file where you provide information about the pages, images and videos on your site and the relationships between them.
This is especially important as your site becomes larger and contains more content, because crawlers can often overlook your content or skip parts of it.
If you have an image sitemap, you can ensure all your content (including image files) is indexed by Google.
How to write an Image Sitemap?
You have two options:
Use a separate sitemap to list images
Add image information to an existing sitemap
When your image sitemaps are ready, send them to Google via the Search Console Sitemaps tool.
For other search engines, you'll need to add a line of code in your robots.txt file.
Topical relevance of the page where images are featured
Another factor that influences the image ranking is the page relevance.
You need to ensure the image is 100% relevant to the page it's on, and the content it's surrounded by.
For example, if your image is of outdoor furniture, and the article is about how to beautify your outdoor area, there is topical relevance.
What you should be aiming to do is to strategically use images to enhance your content and provide a better experience for users - such as helping them understand the information. If you do this, the topical relevance comes naturally.
Authority of the page where images are featured
Not all websites are experts in all topics. As Google spends more time crawling and indexing your pages, your site gains authority.
In Google Image Search, as in regular search, an image benefits greatly from the authority of the page it's on.
What does this mean for image optimization?
It means you need to consider where you are placing images if you want them to rank higher in results.
Page authority is based on three factors:
Age and trust: Pages with a good track record and have been around for years have earned their place in the rankings.
Amount of value received from links: Internal and external links pointing to a page will pass on link authority, which influences the page authority.
Freshness: Search engines like pages that are frequently updated.
When it comes to the importance of mobile-friendly design, there's no arguing with the stats:
Smartphone penetration in the U.S. reached a whopping 85% in 2020. And the majority of those people are searching using their mobile device. Moreover, users search on Google Images more from their mobile than from desktop.
That’s why mobile-friendliness is one of the most important factors for image optimization.
If your pages and images don't appear correctly on different devices, your content is going to be less user-friendly, and that means you’re far less likely to rank high.
Use Google's Mobile-Friendly Test to test how well your pages work on mobile devices, and get tips and feedback on what needs to be fixed.
Linked to mobile friendliness, a key factor in ranking in image search results is ensuring you use responsive images.
Responsive images are critical for ensuring users can view your images in the best quality on any type of device.
If your images aren't responsive, the page won't appear as attractive and easy to view on mobile as it does on desktop, which not only negatively affects SEO but also deters users.
Some website hosting services will automatically ensure your images are responsive.
Otherwise, you can use the <img srcset> attribute or <picture> element to specify responsive images.
The srcset attribute lets you specify different versions of the same image for different screen sizes.
However, Google explains how some browsers and crawlers do not understand these attributes, and recommends that you specify a fallback URL via the img src attribute.
Example of <img srcset>
<img srcset="example-320w.jpg 320w,
sizes="(max-width: 320px) 280px,
(max-width: 480px) 440px,
src="example-800w.jpg" alt="responsive web">
Image captions and SEO friendly alt text
Image captions and alt text is what gives search engines and users context around your images. There are lots of different tags, from image file names to alt text, so make sure you tick each of the boxes.
How to tag images for SEO
1. Image Name
The name of your image file is one of the most important tags for image optimization.
SEO is all about helping search engine crawlers understand your content and how your users interact with it, so your image file name needs to reflect that.
Adding keywords in the image file name (e.g. Samsung_accessories.png) is critical for Google to correctly index your image and make it findable by keyword search. However, your don't want to risk penalties from keyword stuffing.
As Google expert Matt Cutts says:
“Image names and alt texts are best when they’re short, but descriptive.”
A good rule of thumb is to keep length of image names to between 8 and 16 characters.
This length means you can include 2 or 3 keywords - enough to help Google understand your images without tempting you to do keyword stuffing.
2. Alt Text Attribute
Alt attributes are there to help search engines understand the content of your images.
You're probably wondering the difference between alternative text, ALT text, ALT Tag, ALT attribute. We're going to let you in on a secret - they're all the same thing.
The most correct term is “alternative text attribute” but whichever term you choose to use, they are all talking about a textual alternative to the image.
The alt tag should describe what’s on an image and the function of this image on the page. Therefore, any time an image has a purpose on your page, you need to ensure it has an alt tag.
Alt text performs three functions:
Accessibility for visually impaired users. Including alt text ensures that screen readers will be able to read the content of the alt text, allowing the image to be accessible to those with visual impairments.
Back-up. Alt text is displayed in place of the image in browsers where the file cannot be loaded. Therefore people will still know what they were supposed to see.
SEO: Alt text helps search engines determine the content of the image, which will help the image rank well in Google Image and have a positive impact on your whole search engine optimization.
How to write optimized alt text
Alt text should focus on content and function. In other words, your alt text must describe your image, and explain why you use it for.
Aim to make your alt tags as descriptive as possible. A good way to do this is to look at the image and consider how you would describe it to some who cannot see it.
Here’s an example by Moz:
The highlighted text shows the alt text of the image.
Here’s another example. Let’s say you are writing alt text for the image of delicious blueberry muffins below:
Image Source: DownShiftology
A good alt text would be:
<img src="blueberrymuffins.png" alt="Tower of blueberry muffins with blueberries in bowl">
Title Text Attribute
Another important tag is the title text attribute, though it's less important than the file name and alt text attribute when it comes to image SEO.
The image title text attribute is what you see when you scroll over an image, therefore it plays a role in improving the user experience.
The figcaption image tag is often displayed under an image to provide the user with more information about the image.
This is probably the most underutilized SEO and marketing tool - research shows that users focus 60% more on figcaption texts than on the paragraphs that surround the pictures. So, there's a lot of potential to use the relevant text to improve the user experience, and therefore SEO.
Image load time
Website speed is an important SEO ranking factor. We've already talked about how page loading-time can dramatically impact your ranking position and user experience for your site.
If you don’t optimize them, images can actually have a negative impact on your SEO because of their size.
The bigger the image, the longer it takes to load. And it's no secret that site speed is one of the most important factors used by Google's algorithm to rank websites.
Pages with long loading times are also bad news for user experience. This can wind up increasing your bounce rate, reducing visitor return rates and even causing negative reviews - all of which can impact your conversions.
Image Source: Think with Google
On the web, the smaller and lighter the files you upload, the quicker they’ll load on your page—thus helping you rank faster.
There are a few key actions you can take to improve image load time:
1. Choose the best file format
Choosing the right image formats makes a difference.
JPEG is the most common image format on the internet and should be used for images where the quality matters, such as product photography.
JPEG files can be compressed tremendously, which leads to quality images with a relatively small file size.
PNG pictures have better quality and size than GIF images, and are really good for graphics or icons. Do not use them for photography because the ratio quality and size is much better with JPEG.
WebP can be used for both photos or images. A study by Google demonstrated that WebP files achieve an average of 30% more compression than JPEG without loss of image quality. This means you should prioritize the use of WebP over JPEG or PNG, as it will positively impact loading time for web pages.
Also, WebP was developed by Google and Google tends to favor its own products!
2. Reduce file size
3. Use AMP markup
Google Images uses an AMP logo to help users identify pages that load quickly and smoothly. AMP stands for Accelerated Mobile Pages, and since 2016, Google has given priority to pages that use this mark-up, as it allows websites to provide a better experience for mobile users.
Therefore it's worth turning your image host page into an AMP to decrease page load time.
Creating an AMP page can usually be done through a plugin via your Content Management System, or you can add directly to the code.
Use Schema to communicate context
Google states in their Image Publishing Guidelines that structured data can help them to index and rank your images better:
"By adding more context around images, results can become much more useful, which can lead to higher quality traffic to your site. You can aid in the discovery process by making sure that your images and your site are optimized for Google Images."
If you add structured data, Google Images can display your images as rich results. This means the search engine will include a prominent badge to give users relevant information about your page, which helps drive better targeted traffic to your site.
How do you add image structured data?
For Google Images, you can “label” your images in structured data as a product, video or recipe, depending on what’s more relevant to you and your users.
Google provides detailed guides on how to add structured data, like this one for products.
It's important to follow Google's general guidelines for structured data to ensure your images are correctly indexed and will appear in Google Images search results.
Tools to help you analyze image optimization potential
You can compress your images with software such as GIMP, Photoshop, or Illustrator. But if you don't have access to software, a quicker method can be to use online compression services:
Using WordPress? A great tool is ShortPixel, which can also convert your JPEG into a WebP file format if needed.
Imagify and WP Smush are also excellent alternatives for image compression and optimization on WordPress.
To check your site speed
Not sure how fast your site is? Check your site speed with PageSpeed Insights.
This will show you how fast your speed is and provide feedback on how to improve.
Start ranking today
Image SEO is essential for every website. It will change how Google sees and ranks your images and web pages, while also improving website traffic and user experience - and at the end of the day, that should be the goal for any search engine optimization.
We've covered a lot in this article - some actions are quick and easy to apply today, while others may take more web development expertise and dedication of resources. If you're not sure where to begin, we can help. Claim your FREE website audit today and find out the opportunities to improve your digital marketing - from image SEO to PPC campaigns, Facebook ads and much more. You'll get a full audit of your digital marketing assets AND we'll help you understand the opportunities for revenue-busting growth with a 6-month multichannel game plan. Get your FREE audit today!