Image optimisation is one of the most critical (yet forgotten) steps to take under the SEO umbrella.

We all know that heavy images slow down a site, and that speed is a significant factor for SEO. In fact, website visitors expect the pages to load swiftly. If it doesn’t, they will not wait around and immediately click off the site.

Statistics confirm that 53% of consumers will abandon a mobile site if it fails to load within 3 seconds. The same Google research also shows that the probability of a bounce increases by 32% when the page load time spans from one to three seconds. Consequently, it increases 90% when the load time falls between one to five seconds and a whopping 123% when a site takes longer than 10 seconds to load.

Losing this staggering number of traffic can ultimately result in fewer conversions and less profit for your website. Google also measures site speed when it crawls sites and rewards fast sites with a higher SERP ranking.

This is where image optimisation becomes a critical part of your SEO strategy.

What is image SEO optimisation?

Image optimisation requires delivering high-quality images in the right format, size, dimension, and resolution to maintain user engagement. In addition, the process refines the visual files to lighten the server space, speed up load times, and lessen the burden on network resources, such as mobile data plans.

It also includes accurately labelling the pictures so search engine crawlers can easily identify and understand page context.

As a result, your site will experience fast loading, excellent user experience, and improved visibility.

Let’s discuss some of the best ways to optimise images for SEO below.

1. Add names to your images

It is essential to descriptively name your images with relevant keywords to rank your image in search.

Crawlers don’t only index your text, but they also search for keywords within your image filenames. Therefore, the name of the image file will help search engines determine what the picture is about.

You should also include a keyword you are trying to rank for when writing the image file name.

For example, if you are an eCommerce store selling watches, you can name the file as “brandname-watch-model.jpg” instead of leaving it as the default “IMG4809.jpg“.

2. Choosing the right file format

The proper file format of the image also plays an important role. These days, the most popular formats are:

JPEG: You can adjust the quality level of the image as per your requirements. The biggest advantage of using this format is that it keeps file sizes small. It is also well supported if you don’t need images with transparent backgrounds.
GIF: It is used for short and simple animations with a limit of 256 colours. However, it does offer reduced file size and transparent background to simple image files.
PNG: PNGs can be an excellent alternative to both JPEGs and GIFs. It comes with a large file size, but PNG produces a much better image than other formats. It supports transparency, has a better colour range, and has an automatic gamma correction ability.
SVG: SVG files are ideal for logos and icons. These files are light and work well with visuals that have simple illustrations and limited colours.

Consider the role of the image on your site, and then decide the type of file format that will fit the image best.

3. Compress the file size of your images

The heavier the file, the more time it takes to load. And the viewer will easily find an alternative if the web page takes time to load.

This is one of the prime reasons you should compress the file size before uploading it. There are standard photo sizes that you should follow when using pictures on a digital platform.

WordPress has plugins enabled that will help you automatically compress graphic files on your website. You can also do this using Squoosh (for JPGs), Photoshop (most formats), TinyPNG (for PNGs), and SVGOMG (for SVGs).

Another way to shorten the delivery time of pictures is by integrating a Content Delivery Network (CDN). With this process, the cached versions of your images will be stored in multiple geographical locations. They will be delivered to the viewer from the nearest point when they request. As a result, the images will load faster.

If you need help, contact our hosting experts, as optimisation and CDNs are included as part of our managed WordPress hosting plans.

4. Create image sitemaps

By creating a sitemap, you’ll help the search engine robots find your website images and index them better.

Commonly, websites already have sitemaps. If you are using WordPress as your CMS with an SEO plugin, the sitemap is automatically generated for the content page.

All you need to do is to include more data in the current sitemaps so you can tell the search engine “crawlers” the exact location of your images.

Google also encourages sitemaps and advice on creating separate image sitemaps. According to them, a sitemap dedicated to pictures will provide more information to the search engines and enable them to seek out even those loaded by JavaScript code.

5. Add Image Captions

The image caption is a text that appears under the pictures. They help point out who is in the photograph or describe what is happening.

According to Google’s guide for Image Best Practices: “Google extracts information about the subject matter of the image from the content of the page, including captions and image titles.”

They are also helpful for the users as it makes the page scannable. A study by KissMetrics found that captions are read 300% more than the main context itself. It will also keep the visitors on your page longer and reduce the bounce rate.

When writing the captions, keep them clear and concise. Generally, two to three sentences are sufficient to relate the information in your post.

6. Use responsive images

Going responsive is the best way to make sure your website looks good on all device types, regardless of screen size.

When you add an image to your website, you can make it responsive using the HTML code srcset.

The srcset attribute specifies the URL of the image to use in different situations. It will alert the browser to modify the images according to the screen size of the viewers.

If you are using WordPress, you are in luck as the system automatically takes care of the srcset.

However, for other CMS, the code will look something like this:

7. Use alt text

Adding alt-text is another way to enhance images for SEO. It is one more part of the page that you can use to signal the search engines.

You will have to set the alt-text for every image that you upload to your website. It will show up in place of your picture if the browser has trouble loading it for some reason. It will also help the visually impaired users who are visiting your website via a screen reader.

Make sure to update the alt text for your images continually. You can add your focused keyword for the page and something descriptive about the photo itself.

8. Be aware of copyright

Copyright is one of the most common issues found in the digital world. The rule prohibits website owners from using a photo that is owned by someone else without permission.

The US Digital Millennium Copyright Act (DMCA) can notify you if you violate any copyright rule. The consequences of not following the law can also result in serious legal action that includes fines and penalties.

So, you have to be very careful that the content or the images you are uploading are unique and not copied from anyone.

The best way to avoid the issue is to use custom images that you have shot yourself. These original images are a huge plus from Google’s point of view. You can also take help from stock photo agencies, but make sure you follow their licensing rules.

Wrapping up

Now it’s your turn!

The importance of image optimisation should never be neglected, as website traffic is also dependent on this factor.

Give the above techniques a try and find a drastic improvement in the search engine visibility of your website. So, good luck, and I wish you happy optimising!

8 tips to optimise images for SEO