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Optimize Images for SEO: Selection, ALT Tags, Compression

Optimizing images for the SEO and the website involves reducing the image file size without significantly compromising quality. This process enhances your web pages’ speed and user experience. In addition, you need to select the right images for your posts and optimize them with appropriate tags. Explore why it is necessary and how it can benefit your website.

The current article is "2.20. Optimize Images for SEO" of our Complete SEO Guide Box.
Previous Article: 2.19. Link Cloaking. Next Article: 2.21. Embedding Multimedia

Benefits of Optimizing Images

The Importance of Optimizing Images for SEO

One of the primary reasons you need to optimize images for SEO is that it significantly improves page load speed. Images usually constitute the largest files on a web page. By minimizing their size, you can decrease the loading time of your page, thereby offering a superior user experience. Websites that load faster have higher engagement rates, increased conversion rates, and lower bounce rates.

How Optimizing Images Reduces Bandwidth Usage

Another advantage of image optimization for the web is that it reduces bandwidth usage. Optimized images consume less bandwidth, which benefits both the website owner and the visitors. It can help reduce your website’s hosting costs and make it more accessible for users with slower internet connections or limited data plans.

SEO Ranking

Optimizing images is essential in improving your website’s SEO ranking. Search engines like Google consider image optimization part of the page load speed when ranking websites. Therefore, faster websites are more likely to rank higher in SERPs.

Enhancing User Experience

Large images slow down a website, resulting in a poor user experience. By optimizing your images, you can enhance the user experience, which will lead to more extended site visits and higher conversion rates.

A Benefit for Mobile Users

Optimizing images is particularly beneficial for mobile users, who often have slower internet connections than desktop users. By optimizing your images, you can improve the experience for mobile users, who constitute a significant portion of internet users.

How to Optimize Images for SEO on Your WordPress Website

Selecting High-Quality, Relevant Images

To optimize images for SEO, start by choosing high-quality images relevant to your content. These images should enhance your posts visually and provide value to your readers. The “Alternatives” section of the Yoast guide about selecting images has some sources for high-quality images. You can also use Image Generative AI tools that provide royalty-free images.

Make sure you have the right to use images on your site. Use your images, buy rights to them, or use those available under Creative Commons licenses or royalty-free. Always credit images when required.

Resizing and Compressing Your Images

Large images can slow down your site, negatively impacting your SEO ranking. Before uploading images to WordPress, resize them to fit and compress the appropriate dimensions. You can use tools like Photoshop, GIMP, and RIOT Image Optimization Program.

Using Responsive Images

With many users accessing websites on mobile devices, it’s crucial to have responsive images. When you upload images, WordPress creates different sizes for each one. Ensure your theme supports responsive images to serve the right size to different devices. Astra theme should not have an issue.

Implementing Alt Text for Your Images

Alt text is a short image description that search engines and screen readers can read for visually impaired users. When you upload an image in WordPress, there’s a field for alt text. Ensure your alt text is descriptive and incorporates relevant keywords to optimize images for SEO.

Including Captions and Titles

Titles and captions offer additional context for your images. In WordPress, you can add titles and captions when uploading images. While they aren’t as critical as alt text for SEO, they can provide more information to your readers and potentially improve user engagement.

Implementing Lazy Loading

Lazy loading is a technique that loads files, and in this case, images as they become visible on the user’s screen, improving page load times. If you use WordPress, it has built-in support for lazy loading. If your theme doesn’t support it, you can use plugins like a3 Lazy Load or WP Rocket to optimize images for SEO. Astra theme supports it without issue. However, lazy loading on the initial images can lower the user experience. We will cover the Why and How to Turn Off Lazy Image Loading for Initial Images in our Complete SEO Guide Box article.

Creating Image Sitemaps

Image sitemaps navigate search engines to discover your images easily. If your site heavily relies on JavaScript, this is especially important. WordPress Plugins like Yoast SEO or All in One SEO Pack can automatically generate image sitemaps to optimize images for SEO. Section 5 of our SEO Guide will set the Yoast SEO WordPress plugin to generate XML Sitemap while adding to Google Search Console.

Monitoring Image Performance

Regularly check your website’s speed and performance using tools like Google PageSpeed Insights or GTmetrix. Look for any image-related recommendations and implement them to optimize images for SEO.

A permalink is a permanent URL pointing to specific content. It is essential to optimize images for SEO by providing a stable, unchanging web address so search engines can easily crawl your site’s structure and content and users can easily navigate it, providing a better user experience. Similarly, descriptive, keyword-rich file names for images, documents, or other files uploaded to your website enhance SEO by giving search engines valuable context.

Both elements, crucial in constructing a well-structured URL, contribute significantly to SEO as they ensure URLs are concise, clear, and keyword-relevant, improving user experience and boosting search engine rankings. This was discussed in The URL Structure and Permalinks in Posts and File Names article of our Complete SEO Guide Box. You can check it for more URL structure and file name optimization tips. Here are some of the best practices for optimization.

Choose Descriptive Filenames

Optimize images for SEO by using descriptive, keyword-rich file names. For instance, instead of naming your image “IMG0001.jpg,” use “vintage-red-car.jpg.” Search engines use these file names to understand what the image is about.

Incorporate Relevant Keywords

Include relevant keywords in your image filenames whenever possible. This practice helps your images rank for those specific terms in search engine results, enhancing your page’s overall SEO.

Opt for a Simple, Clear Structure

Keep your image filenames and URLs short and straightforward. A concise URL is more user-friendly and more accessible for search engines to crawl.

Use Hyphens to Separate Words

Separate words in image filenames using hyphens, not underscores. Search engines recognize hyphens as spaces, which aids in better indexing of your images.

Stick to Lowercase in URLs

Always use lowercase letters in your image URLs to avoid issues with case sensitivity, which could lead to 404 errors or duplicate content problems.

Organize Images with Subdirectories

For sites with numerous images, organize them into categories using subdirectories in your URLs. This approach not only aids in SEO but also keeps your site well-structured.

Avoid Dates in Image URLs

Unless necessary, refrain from including dates in your image URLs. Dates can make URLs longer and less adaptable over time.

Maintain a Consistent URL Structure

Employ a consistent URL structure across your website for better indexing and an improved user experience.

How to Optimize Images for SEO: Online vs Offline Compression

Optimizing Images is a crucial process in web development, specifically for WordPress, regarding enhancing website performance and user experience, which are essential for SEO. It involves reducing the file size of your images without compromising their quality, thereby ensuring faster loading times and less bandwidth usage. But the question that often arises is: which is the better method for image optimization – using WordPress with optimization plugins or performing the optimization offline on your computer before uploading the optimized result to WordPress? Let’s delve into these methods to make a decision.

Optimizing Images Using WordPress Plugins

WordPress, a popular content management system, offers numerous plugins for optimizing images. These plugins can automatically compress and optimize your images as you upload them to your website. However, while these plugins are convenient, they may not always provide the same optimization level as offline programs.

One of the drawbacks of using WordPress to optimize images is that you must upload your large, uncompressed image to WordPress first and then compress it there. This process consumes more time and bandwidth and leaves the original, uncompressed image on your hosting.

This original image, which you typically don’t use after compression, takes up valuable storage space on your hosting server. Of course, you can delete it, but that’s an additional step that could be avoided. Moreover, constantly deleting unused images can become a tedious task, especially if you’re dealing with a large number of images.

Offline Image Optimization

On the other hand, offline image optimization allows you to compress and optimize your images on your computer before you upload them to the WordPress site. This method offers several advantages.

Firstly, offline optimization often provides more advanced features and better compression rates than WordPress plugins. This is because offline optimization programs are designed for image compression and offer a more comprehensive range of tools and settings to fine-tune your images.

Secondly, after optimizing your image offline, you store the original, uncompressed backup on your computer and upload only the tiny, compressed image to your WordPress site. This approach saves you from unnecessarily using your hosting storage with unused images. It also reduces the time and bandwidth required to upload images, as you only upload the optimized versions.

Optimizing Images Offline Before Uploading to WordPress

We will use the RIOT program for Windows to optimize our images for the rest of the Complete SEO Guide Box.

Always make backups of your images to have the original in case you need to reoptimize.

While WordPress image optimization plugins offer convenience, they may not always be the most efficient or effective method for image optimization. With its advanced features and better storage management, offline image optimization is often more beneficial. However, the choice between WordPress and offline image optimization ultimately depends on your needs, resources, and technical expertise.


You need to optimize images for SEO since it enhances site speed and user experience and improves search rankings. Whether using WordPress plugins for ease or offline tools for precision, the goal is to deliver quality images that load quickly and support your SEO efforts. As web usage becomes increasingly mobile-centric, efficient image optimization becomes vital for a competitive and engaging online presence.

In addition, you need to select or create catchy images that mirror the context of your post to engage the users. Don’t forget to add ALT and other tags. SEO is an ongoing process, so keep updating and optimizing your images as part of your overall strategy.

The current article is "2.20. Optimize Images for SEO" of our Complete SEO Guide Box.
Previous Article: 2.19. Link Cloaking. Next Article: 2.21. Embedding Multimedia


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