Optimize images for SEO, how to optimize them? Does it matter? We often ask ourselves the question of referencing images. We will see that SEO & Images go together well, that it doesn’t take a long time to optimize the images, and that it can bring enormous benefits.

Why is image SEO important?

There are two reasons why image SEO is engaging:

• Google Image
• Semantic optimization

First, optimizing your images for SEO is interesting to gain additional traffic through Google Image. We know that about 68% of Google searches trigger an image block in search results (SERP). From a search point of view in Google Image, I did not find any figures, but we know that in specific themes, the search in Google Image has a lot of weight; this is the case in the travel/tourism sector, for example.

It is, therefore, exciting to work on the SEO of your images to acquire more visibility and more traffic. Of course, it will depend on the theme of the website. In SEO on WordPress, I don’t have a lot of traffic from Google Image. On the other hand, on my travel blog, it works much better.

Second, the SEO optimization of images is interesting to improve the overall SEO of your pages. Today, the user experience is significant; it is even the 3rd pillar of natural referencing. With my SEO clients, I always recommend that each page be at least 1000 words long.

To make this content digestible, you will necessarily use visuals: Gif, videos, and images. Well optimized for Google, these visuals and images will bring more SEO weight to the page. So it’s good for the user experience and good for Google. You will be able to gain visibility and traffic.

How to know the traffic coming from the images

Google has ditched the idea of ​​separating direct organic traffic from images. It is therefore no longer possible to know the image traffic in Google Analytics. Fortunately, it is elementary to see it in the Google Search Console:

1. Go to Search Console – Performance
2. In the search filter “type of search”, replace “web” with “image.”

You will then see the main requests and pages that bring the Internet user to your images. On the other hand, it is not possible to see which page image is bringing the traffic. The data is even minimal.

How to optimize the SEO of images?

Choose the right size.

Too large an image will slow down the site. It should be understood that the images are displayed in specific sizes on a website. Everything will depend on the location of the image (slider, sidebar, wallpaper, small or large image), but an image that is too big relative to its location will slow down the website.

It’s like printing a 10-meter photo to display on a 5-meter billboard. It’s impossible. On a website, it is possible, but it is the total size of the image that will load and not its display size. Each image must therefore be adapted to the size of its location. A logo doesn’t need to be 5000 * 5000px while its location only takes 20 * 20px.

As a general rule, here are the image sizes that I recommend:

• Logo: 50px wide maximum
• Small images: 300px wide maximum
• Medium images: 650 px wide maximum
• Large images: 1200px wide maximum

It all depends on the website; it will, of course, be necessary to adapt. The easiest way is to perform tests to see when the display quality of the image decreases with the naked eye.

Reduce the weight of images

Too heavy an image is also bad for the user experience and, therefore, for SEO. Optimizing images for SEO, therefore, requires weight optimization. First, reducing the size of the images is a good point; second, you have to choose the correct image format; we talk about it in the next point.

Finally, many tools allow you to reduce the weight of images automatically. These tools will optimize and compress the images to reduce their weight significantly. I am using the free online SEO tool Optimizilla.

The maximum weight of an image for SEO is 100Kb.

Choose a suitable format

Choosing the proper aspect ratio is linked to optimizing the weight. A PNG image will be much heavier than a JPEG image. Avoid formats that are too heavy; JPEG is, in my opinion, the simplest solution.

The power of the Alt tag

The Alt tag or alt text is the central element of image optimization in SEO. This is the most crucial criterion to remember. Google cannot read images, the alt tag allows us to describe the image to it, and it mainly uses this description to position the image in search results.

The Alt tag should describe the image and be made up of important keywords related to the page’s content where the image is located. This will strengthen the SEO of the image but also of the page.

Semantic optimization

For better SEO of images, it is recommended to be “surrounded” by relevant semantic terms. If I am talking about pizza on my page, I will add a photo of a pizza and not of a kebab. All the text around the image must talk about the content or at least be relevant to its content and its Alt tag.

The caption of the images

Adding a caption to images improves the semantic field of the page and the image, so it is an excellent practice to improve the referencing of images. Be careful, though; mainly in the images of blog articles, we can use the caption. This will depend on the template used, but it will not be possible to add a caption to images in the background.

The name of the images

In my opinion, the name of the images has very little weight in referencing the images. However, it doesn’t hurt to rename the image with descriptive content. For my part, the name of my images is identical to the text of their Alt tag. It’s always better than a title like IMG9856.

Small subtlety, it is preferable to rename the images before uploading to the site.

Lazyload

The lazyload is a technology more and more used by the web sites. The lazyload allows you to load an image only when you need it. That is to say that the image will load only during the scroll to be displayed at the last moment when the Internet user can see it. This allows for a faster loading time. Without the lazyload, all the images on a page will load simultaneously; it takes longer. Today, many templates offer this option; this is the case of Salient, the template that I offer in my SEO & WordPress online training.

Optimization plugins

Some WordPress plugins allow us to do part of the job for us. This is the case with EWWW Image Optimizer, Wp Smush, or Imagify. I use the latter on my website. It takes care of optimizing all my images after upload, but that does not exempt me from optimizing them upstream. It is also a perfect tool for optimizing all the images in your template, which you often cannot work on yourself.

Mistakes to avoid

The most common mistake is to let WordPress link the image to a media file or be used as an attachment. This will create a new page with only the image displayed. From an SEO perspective, this is a terrible idea as it creates low-quality content. I talk about it a bit more in this blog post. So remember always to select links to “none”.

Also, be careful if you use Yoast SEO; the “yes” box must always be checked in the SEO- Media settings.

Conclusion: the process of optimizing an image for SEO

The rule for SEO images:

• Each image must be less than 100Kb
• Each page must contain less than 1000Kb of images
• Avoid the PNG format, which is heavier than the JPEG format
• Avoid duplicate images

Methodology :

1. Reduce the size of the images: with some exceptions, the immense value of the images must not be more than 1200px. The size of the images must be adequate for their location. Use free tools like Compressjpeg to reduce the size of images.
2. Reduce the weight of images: nothing could be simpler; you can use the free Optimizilla tool or the Imagify plugin for WordPress.
3. Rename images with relevant SEO keywords
4. Upload images to WordPress, then, in “Media”, copy the image’s title in “alt text” to optimize it for Google. As a bonus, add a caption and optimize the text semantically around the image.