For most of us out there, image SEO is limited to just including a keyword in the image alt text.
I wish optimizing images for SEO was that easy. Unfortunately, it’s not.
Images are an important component of web content, and so is image SEO.
Images not just engage the end-users; they also help in sending the right content signals to Google and conquering search results.
With almost 20% of all US searches happening on Google Images, it’s time worth spent on optimizing your images for search results.
Why do image SEO?
Optimizing images is an important on-page SEO activity and helps in faster page load speeds.
Additionally, it’s also a valid ranking and traffic generation opportunity.
For example, here’s a monthly report for one of my personal projects. Clearly, image searches directly contribute (though a minor percentage) to the traffic on my website.
This is additional traffic which has the potential to grow big.
10 image SEO best practices
1. Have a reason for every image
Don’t use images just for the sake of using. There should be a clear purpose behind every image that you use.
Think from the user perspective and always ask yourself one question: does the image help my reader gain something extra?
This gain can be in terms of better content insights , improved layout, breakdown of boredom etc.
If your image doesn’t solve any of these purpose, that image is probably not required.
2. Name your images well
This step is such a no brainer, yet the majority happen to skip it.
Most of us tend to use the system generated name for our images, e.g. DSC160120.JPG. This is no less than a sin for your image SEO.
Always give a relevant name to your images; better include a keyword in the name wherever possible (and without being stuffy).
Moreover, separate your words with a hyphen instead of an underscore. Google treats hyphen as a space and doesn’t play havoc with your keywords.
While your end users are not going to see the image name, Google definitely is. And it gives the search engine some more context about your image, including your focus keyword.
Bad example: running-jogging-walking-tennis-shoes-sneakers.jpg
Bad example: running-jogging-walking-tennis-shoes-sneakers.jpg
Wherever possible, give a caption to your images.
A caption is an explanatory text that appears below the image (and it is completely optional).
It’s not a deal-breaker when it comes to image SEO but it is a great way to show that you care for your users.
Use captions for all images where you think a further explanation will help the user better understand the purpose of the image.
Here’s how you add captions in WordPress:-
Captioned images generally attract user attention and result in better engagement, especially when the majority of the users are going to skim the content instead of reading it end to end.
And in Google’s language “Google extracts information about the subject matter of the image from the content of the page, including captions and image titles.”
Relevant caption, along with right image placement, helps Google identify the context and meaning of your images.
4. Optimize image alt text
Google’s AI technology is advanced enough to identify images with a high degree of accuracy, but it’s still not 100% accurate.
As a case in point, Google can identify Taj Mahal with 92% accuracy. In comparison, a 5-year-old kid can identify the same monument with 100% accuracy.
Google’s image recognition is awesome, but it’s still not perfect.
And that’s where alt-text comes into the picture.
Image alt-text is a direct indication of what the image wants to convey.
It is the text that is displayed when the image fails to render properly on the browser. Also, image alt text is what the screen reader picks when speaking out the content to visually impaired.
Therefore, always write alt text relevant to the image and the content around it. Wherever possible and contextual, include a keyword or its variations in the alt text.
WordPress allows you one single place to enter alt-text and image title, as shown below.
You can also mention alt text through custom HTML using the following tags:-
<img src=”OnPage Champ Dashboard” alt=”OnPage Champ Dashboard showing SERP Audit count”/>
Use OnPage Champ’s SERP Audit functionality to unearth your competitors image alt text best practices .
5. Use the right image format
Most of the images on the web are in JPEG, PNG or GIF format.
The difference lies in the way these 3 formats capture color data.
JPEG, the most widely used image format, is the lightest one with not much difference in picture quality. Majority of your requirements should be fulfilled by JPEG.
But since JPEG doesn’t support transparent backgrounds and varied color range, PNG is the best fit for logos, symbols, text art, transparent backgrounds or detailed imagery.
PNG has the maximum file size amongst all 3 image formats, so use it sparingly and only when required.
GIF supports only 256 colors and is therefore used for simple imagery and animations.
Here’s a comparison of all 3 formats:-
6. Compress before upload
Before you upload your images to your website, optimize them for the web by compressing the images.
Many images are detailed enough for the computer but not for the human eye. Compression reduces the image size without much visible loss of quality.
Here’s an example were compression reduced the image file size by ~60%. Can you spot the difference in quality? I am sure you can’t.
Some of the compression tools can also strip EXIF data of the image like shutter speed, exposure, F number, GPS coordinates, etc.
Having GPS coordinates in the EXIF data can be a double-edged sword: your privacy can be breached by revealing your coordinates (e.g. your profile image may reveal the coordinates of your home).
Contrary, for a local business, EXIF data of an image may reveal the store co-ordinates, thus helping with local SEO (though there’s not much proof of this).
So decide for yourself and handle EXIF data accordingly.
You can use free WordPress plugins like Smush or a website like TinyPNG to compress your images.
7. Scale your images (whenever required)
Most of the time, you will tend to use images whose size differs from the size as specified in your CSS.
Consider this example where we were using an image (from Unsplash) that is 4 times the size specified in our CSS.
This is an unnecessary burden on the network as it needs to fetch a much larger image than what’s actually going to get displayed.
This also severely impacts the page load speed.
You can scale down such images using the PicResize tool. Just copy-paste your image URL, specify the scaled dimension and click “Done” to create a JPG file.
Next, install Media Replace Plugin (for WordPress based websites). You can directly replace the original image with a scaled image using this plugin.
8. Opt for lazy loading of images
Images can make your web content-heavy; thereby impacting page load speed.
And most of the visitors to a web page are not actually going to scroll down till the last item. There’s no point loading all the images right at the start.
Instead, it makes sense to load only the first fold images, and load below the fold image as and when they are required i.e. at the time of the scroll.
This concept is called lazy scroll or lazy loading and you can witness this live on our blog.
If you are on WordPress, there are multiple plugins available for lazy load. We are using Smush at the moment and are quite happy with it.
If you are not on WordPress or want to do this manually, you can refer to this detailed document from Google on how to execute lazy loading using JS.
9. Create an image sitemap
Image sitemap is important for one single reason: you may not rank for text searches but you may rank for image searches for a particular keyword.
Image sitemap gives Google a direct link to all your images, making the crawl easy.
There’s a misconception that sitemaps ensure Google crawls your pages & images. A sitemap just gives an indication to Google that there are assets available that may be worthy of a crawl.
If you are on WordPress, the Yoast plugin allows an easy option to add an image sitemap.
10. Stay relevant to other on-page SEO elements
Your image SEO should be in sync with your other important on-page SEO elements.
That means your image alt-text, title, caption, etc. should be talking about the same idea as does your page title, headings, meta description, content, schema, etc.
This is nothing but an extension of the first point i.e. staying relevant.
If your image is relevant to the page and its content, Google will take this as a positive signal and boost your text as well as image search rank.
Image SEO: Key takeaways
Optimizing images is clearly a low hanging fruit for marketers.
It not just helps in better user experience and faster page load speeds but also results in better ranking opportunities.
So make sure your images are easy to find and are not breaking the user experience, and your image SEO is good to go.
The most important thing to ensure is that you stay within the context and mention the right alt text. In addition, keep the following things in mind while optimizing your images:-
- Use the right image format
- Compress your images
- Use lazy loading
- Don’t forget other on-page SEO
While it may sound like a lot of effort, it’s actually worth the time spent.