Images are a significant part of any website. Yet optimising images for SEO is something many people skip over entirely. While you may spend a lot of time optimising your content, there’s a lot to be gained from image SEO and ranking your images in Google Images.
What is image SEO?
Image SEO refers to the optimisation of the images on a website to increase their visibility in the search engine results pages (SERPs). In the same way that you optimise a webpage for keywords, you can also do the same for your website images.
After all, images play a crucial part in the content of any website. Not only do they help to break up written content, but they also keep users engaged.
The techniques you use to optimise your images for SEO will help them rank much more prominently in the dedicated unpaid images search engines, such as Google Images. These techniques ensure your images are crawled, indexed, and placed for relevant search queries.
How does Google image search work?
There are 3 main methods that Google Image search uses and it’s important to understand these for image SEO. Firstly, you have the traditional search using keywords or phrases on the dedicated image search. Secondly, you have a reverse image search. Thirdly, there are images displayed in the main SERPs.
Traditional image search
Traditional image search is the common method of searching for an image online. It’s where a user will visit Google Images and enter a query for the images they wish to see. The more closely an image relates to this search intent, the higher it will appear.
Reverse image search
Another method of image search is reverse image search. As opposed to entering text to perform a search, the user will upload an image or image link. This feature is known as Google Lens and is typically used to find the source of an image or find visually similar images. It’s also possible to use the mobile app to take a picture for reverse image search.
Images displayed in SERPs
Alongside the two methods above, images can also be displayed in the main SERPs. Typically, this includes a small selection of the highest-ranking images relevant to the user’s search query. These only display for certain searches though and not all searches.
As search engines begin to add images to their main search results, the importance of image SEO continues to grow. After all, images are one of the top SERP features, with research finding they appeared in 37.81% of search results.
There are a few ways images can be displayed in main SERPs:
- Image packs
- Text result images
- Rich attributes
- AI overviews
Here’s an example of how images display in the main search results:
If optimising your images for search results is something you’ve never considered before, there are lots of benefits you can gain by starting! Next, we’ll cover the benefits of image SEO.
What are the benefits of image SEO?
Image SEO is a sure way to ensure your website images will be seen by users in the SERPs. While you may not have paid much attention to optimising images before, there are many benefits.
- Improve engagement and page dwell time by ensuring your images are relevant and provide value.
- Greater accessibility by adding alt text for search engines and screen readers.
- Enhanced user experience by reducing page load speeds and ensuring images render seamlessly.
- Provides an additional source of website traffic as those who click on your image will be directed to your site.
- Ensure your images appear high in search rankings for the different types of searches.
How to rank your images in search results?
The techniques you will carry out for image SEO will differ from those when optimising written content. That’s because, unlike written text, the search engine crawlers that discover your images can’t actually see them.
When a crawler discovers an image, it uses several pieces of information to decipher the image’s contents. Typically, this includes extracting data from the file name, metadata, and surrounding text. This allows the crawler to understand the content of an image.
Therefore, you will need to use several different optimisation techniques to stand any chance of your images ranking. Here are some of the most effective ways you can achieve this:
Pick a suitable file format
One of the first things you need to consider is the file format of your images. While there are many different image formats, only a handful are supported by Google. The file types to pick from are JPG, PNG, WebP, GIF, SVG, and BMP.
- JPG is an image type that uses lossy compression that decreases image quality but provides a small file size. However, it is possible to adjust the quality when compressing the image to find a suitable balance.
- PNG uses lossless compression meaning there is no image data lost. As such, it provides images with better quality, but a larger file size. PNG also supports transparency.
- WebP is an image type developed by Google that uses lossless and lossy. Its compression is more efficient than JPG, providing up to 80% better quality. As such, it is a good file type for balancing quality with low file sizes. As a relatively new file type, older browsers don’t support this file type.
- GIF is a lossless compression image type but is only limited to 256 colours. As such, it is typically favoured for simple graphics and animations as opposed to high-quality images.
- SVG is a vector image type that is widely used for logos, icons, or animated images. Unlike raster images that are made up of pixels, vector images create geometric shapes, such as lines. As a result, the images can scaled to any size without loss of quality or higher file size.
- BMP is another type of image file type that is favoured for large and uncompressed images due to its high quality. However, this does result in a large file size that can make it unsuitable for widespread use on a website.
Find out more about how different image types and compression impact load times and image quality
File names
Another tip for ranking your images in search results is the file name. Whenever you upload an image to your site, make sure you give it a descriptive and keyword-rich file name. This helps crawlers to better understand the image content.
Adding an image that is a string of letters or numbers will not do you any favours. Also, you can’t use spaces in file names. Instead, separate each word with a hyphen. Try to make the file names as descriptive as possible without being too long, for example, “how-websites-and-seo-work-together.jpg”.
High-quality and resolution
Search engines like Google prioritise high quality images with high resolution. That’s not to say every image on your site needs to be in 4K because your page speeds would drastically suffer. However, you need to make sure your images are clear and sharp.
Images that are pixelated or blurry can have the opposite effect. It also makes your website look unprofessional and can detract users from your site. In most cases, an image on your website shouldn’t need to be over 2,500 pixels wide.
The resolution of an image should also be considered. Typically, resolution is expressed as pixels per inch (PPI) or dots per inch (DPI). The higher the resolution, the higher the image quality and file size. In most cases, a resolution of 72 dpi should be sufficient.
When settling on a resolution for your images, it’s much better to opt for a rectangular proportion. Using ratios, such as 16:9, 4:3, or 1:1, are much more favoured by search engines and are more likely to rank higher than an image with extreme proportions.
Alt text
You should also be adding alt text to your images if you want them to rank in Google Images. Alt text provides a text description of an image. These are used when a browser cannot properly load an image or if someone is using a screen reader.
However, alt descriptions are also used by Google to better understand the image content. The descriptions you provide must be as descriptive as possible without keyword stuffing. An example for the image below would be “A young man yelling into a megaphone and pointing his finger”.
Standard on-page optimisation also applies here too. Optimising other metadata, such as page titles and descriptions, can also be beneficial in helping your images rank higher. That’s because search engines also use these when deciphering an image’s contents.
Responsive image scaling
One more method you can use to make your images rank in Google Images is by using responsive image scaling. This allows images to automatically adjust depending on the viewport size (or the size of the screen displaying the webpage).
Not only does it help improve your user experience, but it also ensures images are an appropriate size for users to see them.
Lazy loading
Another option you can use to reduce page speed is lazy loading. This means that images on a webpage don’t load until it is in or near the user’s viewport. As such, page speed rapidly increases as only the content above the fold is initially loaded.
This can be easily implemented by appending a tag to the image code:
<img src=”image-file-name.jpg” loading=”lazy” alt=”Your image alt text”>
Images above the fold should never have the lazy loading tag added as this can seriously affect your First Contentful Paint (FCP). Instead, these images should use the fetchpriority=”high” tag instead.
Image sitemap
You should also consider the use of a sitemap for your images if you want search engines to crawl and index your website images. This can either be done by adding images to your existing sitemap or creating a dedicated image sitemap.
Doing so will significantly increase the chances of search engines discovering the images on your site. After all, if they can’t discover them, they won’t ever appear in search results. Check if your CMS provides the option for this. If not, some free tools or plug-ins can do it for you.
Structured data
Adding structured data or schema markup to your site is highly recommended if you want your images to appear in rich snippets. Often, images in rich snippets can significantly increase the click-through rate as it grabs the user’s attention.
This won’t be relevant in some situations, but recipes, e-commerce listings, and events can mostly benefit schema markup. Alternatively, you can use structured data to provide more detailed info on an image’s license, such as the creator and copyright.
Captions
One more tip you can use to rank your images higher is to use captions. These are short written descriptions that appear directly underneath an image. They provide extra information that makes your content more informative and compelling.
It also helps search engines as they use captions to gain a better understanding of an image. When captions are, on average, read 300% more than body copy this shows just how important captions are.
You don’t need to add captions to all your images. Instead, consider adding it to the images that you are aiming to rank. To write a good caption, make sure the information you provide:
- Helps you better understand the image’s content.
- Includes the relevant keyword you want the image to rank for.
- Is relevant to the content of the article.
Never use text in an image
This last tip goes without saying if you’ve followed all the other tips. It’s recommended that you never place text inside an image. While your users may be able to read (providing the images are responsive), search engines cannot.
All the text inside an image will not help your ranking potential. If anything, it will have an adverse effect. For those reading from another country, this text also cannot be translated, affecting the user experience.
The only instance where it is acceptable to use text in an image is an infographic. Only then, these should be an accompaniment to an article or page on your site that covers the content of said infographic. Specify this in the alt text if you want the infographic to rank.
While it may be something you’ve never given much attention to, image SEO is an effective method for increasing your visibility and traffic. By taking the time to implement the tips outlined above, you stand a much better for ensuring your images are likely to rank high.