While everyone’s main focus is on regular snippets in search engine results pages, you can develop a smart image SEO strategy. If you’re struggling to outrank your competitors, smart image SEO is a nifty way to outrank them.
Search engines know what types of content to return for each query, and queries often produce top-five image results. If your normal page is not in the top 20, an image can help.
What influences the ranking of your images?
Search engines need to be able to easily discover, crawl and index your images. But in the end, popularity, context, and timeliness have the most influence on how your images rank.
Make sure your images are easily discoverable. Including images on pages is not always enough, so I recommend creating image xml sitemaps which list all your images. You can either opt for XML sitemaps that only list your images, or include the images in your regular XML sitemap. Both are suitable for search engines.
Once search engines learn about your images, they need to be able to access them too. In the context of SEO, we call this crawlability.
Make sure your robots.txt file doesn’t block search engines from accessing your images.
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Your images can be discovered and viewed by search engines, but can they also be indexed? When a page has the noindex directive set, no content on the page is indexed – and that includes its images.
4. Page popularity
The popularity of the page the images are on heavily influences the image rankings. Popularity is largely determined by the number of links a page has from other websites.
Try some searches for your favorite actors or musicians. You’ll see resources like IMDB, Wikipedia, gossip sites, and their own personal websites make the top five every time because people happily log on to those.
5. Page relevance to images
Place images on pages that are highly relevant to those images. Suppose you have great photos of a 1967 Ford Mustang on a page devoted to your kittens. The chances of you ranking for relevant queries regarding this car are not high.
But include this image in your blog post detailing how you spent three years restoring your vintage Ford Mustang, and your odds will improve exponentially.
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6. Image captions
Always describe the content of the image using captions. These also add to the relevance of the images, as they help search engines better understand what the images are about. Place the caption text just below the image it describes.
Please note that captions are not only useful for search engines; they are also useful for visitors, as they provide more context.
7. Image file name, alt and title attributes
The filename of an image should be descriptive. DSC00004.jpg is therefore a bad filename for your web photo of a beautiful sunrise in Malibu. A much better filename would be sunrise-malibu-beach-california.jpg.
The image alt attribute is meant to be alt text for the image — it should describe the image. The image title attribute adds extra context – when it comes to image SEO, it’s all about providing context, so use that.
8. Annotate images using Schema
Using Schema to mark up your images is another great way to give search engines context. It provides a very effective and clear way to communicate about your images.
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9. Optimize for speed
It’s important to make sure your images load quickly. To that end, there are two things you need to keep in mind:
- Image compression: Compressing images allows you to drastically reduce their file size while maintaining sufficient quality for an image to be useful. Sometimes it can even result in a 90% decrease in file size. Two examples of tools you can use are TinyPNG and Imagify. TinyPNG also integrates with WordPress, Magento, and other systems, so that’s a big plus in my book.
- Serve the right format: A variety of image formats are available. Using the right format for the right type of image is essential when it comes to optimizing speed. See below which format to use for which purpose:
- PNG: Logos (because it supports a transparent background) and images that need to stay sharp, like screenshots.
- JPEG/JPG: Pictures.
- GIF: animations.
- SVG: Use these so that images can be scaled without loss of quality (vector images), for example for maps, icons and logos.
- WebP: WebP is developed by Google and is an alternative to JPG and PNG. The biggest advantage of the WebP format is that it offers excellent compression support. I highly recommend experimenting with it, as it has a lot of support and potential.
- Serve the right size: if someone is browsing on a cellphone, it doesn’t make sense to serve images that are 2000px wide. Therefore, it is advantageous to broadcast images of different sizes depending on the different devices used.
In this example, we will serve the image with a width of 400px to screens with a window width of 375px and less, the version with a width of 800px to screens with a window width of 376-768px, and the image by default to every device with a window width greater than 768px.
Doing this manually is very inefficient, but luckily there are tools that will do this automatically so you don’t have to constantly think about it.
Some other tools worth looking into that help optimize images (and save time) are: Cloudinary’s website speed test, Google Lighthouse, and GTmetrix.
Bonus: use lazy loading for improved user experience
Lazy loading is a technique which allows you to load images just before they are shown to your visitors.
For example, if you have a high resolution image at the bottom of a page, it doesn’t make sense to load it just as the visitor lands on that page. Loading it immediately costs valuable loading time, and it’s potentially a waste of time and data if the visitor doesn’t even scroll that far.
While this may not help your images rank higher, it has a lot to do with optimizing images and providing a good user experience for your visitors.
Don’t let image SEO be an afterthought
Make image SEO a priority, as it can help you outrank your competition.
Steven van Vessum is Vice President of Community at ContentKing, a real-time SEO app that constantly audits your website for issues and changes. ContentKing is mainly used by companies such as British Telecom/EE and TNT/FedEx.