How to optimize images for SEO

What do 21st century ecommerce customers and Paleocene-era mammals have in common? 

Well, while early mammals probably didn’t have the same nose for online deals that ecommerce customers have, we both nonetheless evolved to respond to the visual stimuli in the world around us. 

That’s a roundabout way of saying that images are a really important part of your website’s digital content offering.

Research suggests that images, along with other types of visual content, make a critical difference to the performance of digital content, generating more engagement, more shares, and more conversions. That being the case, it makes sense to optimize the images on your website or apps, and other touchpoints, for search engines — in other words: search engine optimization (SEO) for images. 

But, while you can optimize written content with keywords, rich text, and structured data, how do you boost your images’ search visibility? 

Don’t worry — in this post, we’re going to explain the SEO process for images, including why and how to do it, and how Contentful can make that job easier. 

What is SEO image optimization?

Optimizing images for organic search refers to the process of increasing the visibility of your image assets in organic search results. 

In more detail, that involves adding certain meta tags to an image, adjusting an image's size and format, and adding descriptive alternative (alt) text — with the goal of improving its search visibility and, consequently, driving increased traffic through the image search results. 

In other words, from an SEO perspective, while it’s true that image optimization lends itself to page performance, it has a more direct connection to driving traffic from image searches.  

Generative engine optimization

While SEO image optimization has traditionally been associated with conventional search engines, nowadays, it should also apply to generative engine optimization (GEO) — concerning the search results produced by generative artificial intelligence (GenAI) search engines. 

Multimodal visibility

Content teams (or whoever is tasked with optimizing images) must think about multimodal visibility during optimization. That means considering all the ways in which an image will be visible to search engines (traditional and GenAI) and includes using, for example, descriptive file names, clear alt text, schema markup, appropriate formatting, the Open Graph protocol, and so on.

You can apply similar principles to video content, adding, for example, accurate transcripts to assist AI processing. 

Why think about image SEO?

If an image is optimized effectively, there’s a good chance that a search engine will rank it higher in image search results (the images tab in Google search result). In fact, research suggests that Google Images results make up around 22.6% of all internet searches, and that half of online shoppers say images of products help them decide to purchase. Those figures suggest that, while image search is often neglected by digital content marketers, it’s nonetheless a valuable source of traffic.

Additionally, by marking up your images with structured data (also referred to as schema) your images may appear as a rich result — also known as a rich snippet. Rich results are an expanded expression of the digital content beyond the link, and help your content feature more prominently in the SERP.

Let’s look at an example of a rich snippet. If you’re searching for “New York’s best pizza,” a rich snippet might include the name of a restaurant, its star review rating, the price range of the pizzas it offers, its address, opening times, and (you guessed it), an image of one of its pizzas. 

Rich snippets are a lot better at grabbing audience attention because they’re an indication of the content that lies beyond the link itself, and so encourage click-through. Search engines use other bits of data to build rich results, including schema markup, but optimized images can increase the chances of a rich result outcome. 

Going beyond rich results 

SEO image optimization isn’t just a strategy to generate rich results. As we mentioned earlier, images play a more significant role in user search behavior than many brands realize. 

With that in mind, while text search results still dominate the search landscape, don’t ignore the SEO value of Google Images, the search engine's dedicated image search function. 

Research suggests that the majority of ecommerce shoppers are influenced by the visual results that search engines deliver — with some even valuing visual information over text when searching for certain products.

The point is, you need to be thinking about optimizing images for their own image search ranking value, in addition to their potential inclusion in rich results. 

So, how do optimized images factor into a typical search journey?

Let’s say you’re still searching for “New York’s best pizza,” and you type your query into the Google search bar. While you’d get the classic vertical list of search results, Google might also generate a range of supporting images that catch your eye: images of restaurants, pizzas, pizza toppings, brand logos, and so on.

If you clicked on one of those images, you’d be pulled into the Google Images search function, where it would be possible to click through to the provider’s page, or continue searching across competing images. 

Opportunity cost is also a key factor that should drive your image optimization efforts. It’s fairly easy to tinker with images, adding schema markup, or alt text, or formatting them appropriately so that they start performing better on Google — and, by extension, on generative engines.

So, while image search journeys can be varied, or less structured than the classic, listed, text search journey, they have an undeniable part to play in SEO — one that a lot of brands overlook. 

Regulatory standards

We’ve been focusing on the potential SEO value of images — how well they boost the conversion rate, bottom line, and so on — but there’s another really important reason to think about image optimization: regulatory compliance. 

The European Accessibility Act (EAA) now requires certain organizations to add alt text to the images on their websites as a means to help visually impaired users navigate content. The act states that the alt text must “accurately reflect the purpose of the image and/or provide an accurate description,” and it sets out several other compliance requirements, such as the need to add accompanying text to explain the meaning of graphs and diagrams. 

And, just a reminder: Don’t stuff the alt text attribute with keywords. This is no place for that. If a keyword naturally appears in your description of the image, then it’s a win-win.

So, with all that said, image optimization doesn’t just make good marketing sense, it helps everyone enjoy the internet a little bit more! 

6 tips for optimizing images for SEO

We’ve seen the value of optimizing images for search, but how do you get that job done? Let’s explore some key considerations. 

1. Think about image quality

Before you even start worrying about adding markup or tagging your images, you’ll need to make sure you’ve ticked the most important optimization box: selecting a decent image.  

This point isn’t rocket science but, while there’s going to be a degree of subjectivity in selecting a “good” image, you should think about how visually appealing the image is, how it breaks up other content on the page, how credible it is if it’s a graph or a chart, whether it matches your brand’s voice and identity, and so on. 

Don’t underestimate how important high-quality images can be as part of your content’s overall impact, especially given its potential value to image search. 

2. Select the right image format

As much as you think about what you’re displaying, you should also be thinking about how you’re displaying it — and select the best digital format for your image. 

Again, while there’s no single “best” option, certain formats are better suited to certain types of image: scalable vector graphics (SVG) for logos, web picture (WebP) for compressed images, and so on. Search engines examine your image formats and consider factors like load time (more on that later), so it makes sense to think about which format is going to serve your content needs best. 

3. Optimize image file names

What you call your image file is relevant to its search performance. With that in mind, you should aim to be descriptive and efficient. For example, an image of a pepperoni pizza should be named (something along the lines of) pepperoni-pizza-takeaway.png, rather than pizza1.png, or pepperoni-pizza-hot-with-stuffed-crust-available-for-takeaway.png. 

File-name efficiency is also going to help if you need to translate text for foreign users, or if you’re going to use an artificial intelligence (AI) auto-tagging feature to add alt text to the image (more on that below). 

4. Use descriptive alt text 

Alternative text (alt text) is metatext that is stored in the code of the webpage that describes an image to search engines, and helps boost search rankings.  

Alt text obviously should be descriptive in the sense that it captures what the image is, and may include keywords for the search engine algorithm, if it’s possible to add them naturally. Alt text should be concise to promote clarity and also avoid repetition. So, if you had a photo of a pepperoni pizza in a takeaway box, your alt text could be (something along the lines of): “pepperoni pizza in a takeaway delivery box.”

Alt text is coded as an attribute to the associated image tag. So, for our example above, the alt text would read: <img src="pepperoni-pizza-takeaway.png" alt="pepperoni pizza in a takeaway delivery box">. 

If you’ve got a large volume of images to manage on your website, it’s often a good idea to integrate an artificial intelligence (AI) tool to add alt text to those images automatically. AI alt text tagging is a way to scale your content offering, and eliminate tedious manual tasks from the content workflow. 

You can explore that potential for yourself in Contentful’s AI Actions feature which automatically analyzes images, and generates alt text for you in seconds. 

5. Compress and resize images

If images are not properly sized for the devices they’re loading on, they can slow down load times — an issue that search engines will pick up on and count against the SERP ranking. That means you need to think about image dimensions and breakpoints for each device on which your images will be presented (desktop, mobile, store display, etc.) and make sure you’ve applied the right one for the digital channel. 

Images over a certain file size can also cause loading issues. With that in mind, you should always seek to compress large images, which just means that you’re reducing the file size without compromising its quality. 

Leverage technology as much as possible to size and compress your images correctly. For example, Contentful’s headless content management system (CMS) can automate your sizing and compression needs with responsive images. That functionality eliminates any risk that an image won’t display properly on a specific device or channel, and end up hurting your ranking by slowing down the load time of your page.  

6. Test and experiment

Image optimization is not a one-and-done exercise — you can constantly iterate on the images that you use in a piece of content, changing their size, placement, and so on, until you land on something that chimes with your audience. You don’t need to use guesswork here, either — you can perform A/B tests to gather hard data on which images drive conversions, and then implement the best variants on your live site. 

If you’re looking for a testing and experimentation tool, Contentful has that covered too. From A/B tests to AI-supported content suggestions, you can use our tools to automate most of your testing strategy. 

Optimize with Contentful 

Don’t leave clicks on the table by neglecting your digital image content. Start thinking differently, with Contentful. 

From testing and experimentation, to fine-tuning alt text, Contentful has the tools you need to unlock the SEO potential of your images, boost your content’s ranking, and, ultimately, drive conversion and sales.  

Our digital experience platform (DXP), empowers you to build any kind of content experience in a completely composable environment. For example, the Contentful headless CMS makes it possible to upload images, or any digital content, quickly and easily, across any channel, with no risk of formatting or coding complications.

Meanwhile, Contentful Personalization streamlines your publication process, adding AI-generated metadata to images automatically, and even making real-time suggestions to optimize the visual appeal of your customers’ journeys. 

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