What is an optimized image?

A well optimized image for the web must be a file whose size is reduced to the maximum, while keeping a good quality. This allows to keep an optimal loading time for your site.

On the other hand, the optimization of a visual also concerns the SEO. Just like text or video content, images are ranked by search engines. It is therefore necessary to work on their tag and attribute, using keywords, to hope to rise to the top of the search results.

How to find free visuals?

To help you find the perfect image to illustrate your content, many image banks have emerged. These free online platforms, such as Pixabay or Pexels, allow you to download photos and illustrations in various formats and sizes. Other paid image banks, such as Shutterstock, offer even more choices.

Please note! In France, although these visuals are delivered free of charge, it is necessary to mention their credit under each publication, as well as their origin in a paragraph of your legal mentions.

You can also ask your client or supplier to share visuals with you, provided that they have the rights to use them.

JPEG or PNG: what is the ideal format for the web?
The first thing to define before publishing your image online is the format of your file. Should you choose JPEG or PNG for your website?

JPEG (.jpg) is the standard format used on the Internet. It is a compressed format: the weight is reduced and the quality is maintained.
The PNG (.png) is a format with more colors. It is often quite heavy, but it allows the use of transparent backgrounds.
Also, use JPEG when you integrate a photo or a computer graphic. Use PNG when you publish a logo or any other type of image that requires transparency.

To modify the format of your file, you will need to use an image processing software such as Photoshop or GIMP. The latter is totally free and offers almost as many features as a professional software.

Better yet, to manage the transparency of your image, and play with different backgrounds, try the free tool : Remove.bg.

Optimize the weight and size of your images
The loading time of your website is taken into account by Google. And very often, the weight of your visuals can alter the performance of your web pages. The faster you display your images, the better your ranking will be! Your visitors also appreciate finding fast, easy-to-use information and large, true-to-life visuals. This greatly enhances the user experience.

Thus, the ideal weight of a visual on the Internet should not exceed 100 kb to 150 kb. Easy to say, but difficult to produce! To reduce the weight of your images, you can start by reviewing its dimensions. On the web, a photo, a thumbnail or even a banner usually doesn’t need to be larger than 800 pixels.

The image editing software Photoshop or GIMP allow you to make this modification. Even faster: free tools like IloveIMG will do the work for you!

Name your visuals carefully
If Confucius said “A picture is worth a thousand words”, he was far from suspecting that on the web, a visual without information has little value! Now that your image is ready to be published, it is essential to work on its textual part.

When search engine crawlers analyze your web page, they also read the text of your photos. Start by creating a relevant file name: it must describe the image and use your keyword.

Fill in the tags of your images
Today, CMS like WordPress, Prestashop, Shopify, Magento etc. offer you many fields to fill in when you import media. This is called tag or attribute. They contribute to a better natural referencing.

The Title tag
With the help of this “Title tag”, you indicate to the crawlers important information about the subject of your image. Choose a short title related to the content of your page.

For example: Pair of converse chuck taylor all star

The ALT tag
The “alt” attribute for “alternative text” is a textual description assigned to an image. This statement is displayed instead of the visual if it is not displayed correctly. This tag also allows visually impaired people to access your images. Digital accessibility is also valued by search engines. Think about it!

This replacement text must describe the image and its context in just a few words. It must be consistent with your content and contain about 5 words. It is not necessary to write a detailed description. And, of course, it is strongly discouraged to accumulate a lot of keywords.

For example: chaussures converse montante anthracite

The long description
The “description tag” allows you to provide longer information on the visual. It is not displayed on the front of your website, but remains particularly important for your SEO. Do not hesitate to use one of your keywords to describe the image and its environment.

Create a sitemap image
When you put your website online, you have certainly edited a sitemap in order to index all your pages. Did you know that it is possible to perform this action for your images ?

A sitemap is a file, which details in the form of lines of code, the information that you want to reference on search engines. You can then create sitemap for :

the web pages,
the categories of your site,
the images presented,
published videos, etc.
This textual document contains the whole structure of your content. It helps search engines’ indexing robots to explore, identify and understand it, in order to update it regularly.

or the most advanced, adding a sitemap requires to insert a line in your robots.txt file. The latter indicates to the crawlers what to index or not of the current web page. Fill in the path to your sitemap image and transfer your file via an FTP like FileZilla.

If you are not comfortable enough to touch the root of your website, send the sitemap using the search console (GSC). This free tool offered by Google, collects data to help you optimize your pages, and track your SEO performance.