Digital Growth Marketing & Transformation for small businesses

3. Organic SEO

3.3 How to Optimise Images for SEO: A Comprehensive Guide

Images play a crucial role in enhancing the visual appeal of your website, whether it’s an eCommerce store or a blog. However, if you don’t optimise your images for SEO, they can actually hinder your website’s performance and rankings on search engines. In this comprehensive guide, we’ll explore the best practices for optimising images for SEO to improve your website’s visibility and increase organic traffic.

Why Image SEO Matters

Before we dive into the details of optimising images for SEO, let’s understand why it’s important for your website.

  • Improved Page Speed: Adding large images to your product pages and blogs can make them heavy and reduce your Google page speed. Slow-loading pages can lead to poor user experience and lower search engine rankings. Optimising your images can help improve your page speed and provide a seamless browsing experience for your visitors.
  • Enhanced User Engagement: High-quality and visually appealing images can captivate your audience and encourage them to stay longer on your website. By optimizing your images, you can ensure that they load quickly and retain their quality, thereby increasing user engagement and reducing bounce rates.
  • Higher Search Engine Rankings: When you optimise your images for SEO, you increase the chances of ranking higher on search engine results pages (SERPs). Properly optimized images can appear in Google’s image search results, driving additional organic traffic to your website.

Now that we understand the importance of image SEO, let’s explore the key steps to optimise your images effectively.

Step 1: Choose the Right Image Size

The size of your images is a critical factor in optimising them for SEO. Using oversized images can slow down your website and negatively impact user experience. On the other hand, using undersized images can result in poor image quality and pixelation. To strike the right balance, follow these guidelines:

  1. Determine the Image Dimensions: Assess the space available on your website where the image will be displayed. Measure the width and height requirements, and ensure that your image dimensions match these specifications. If the site has already been coded and you are looking at this for a blog article, the best way of doing this is to use the inspector tool in Chrome. Right click on the image that you want to replace or where the image currently is located on the page and click inspect. When hovering your cursor over the image in question you should see a tooltip that explains the about of pixels that the image currently take up on the page. If you have the dimension setting at the top of the page set to “Responsive” you can resize the page to see how the dimensions of the image change at different screen sizes. Broadly speaking you should upload an image that works on the largest screen size, unless you are creating a page specifically for a certain type of traffic, like a mobile landing page for example.
  2. Consider Image Resolution: While higher-resolution images offer better clarity, they also come with larger file sizes. Find the sweet spot where your image resolution is optimised for both quality and file size. Aim for a resolution of 72 pixels per inch (PPI) for web images.
  3. Compression is Key: Use image compression techniques to reduce the file size without compromising image quality. Tools like Adobe Photoshop offer excellent compression technology, allowing you to adjust the image quality while keeping the file size to a minimum. Alternatively, you can use free online tools like TING PNG, or Website Planet’s image compressor to compress your images without losing quality.

Step 2: Optimize Image File Formats

Choosing the right image file format is crucial for optimising images for SEO. While there are various file formats available, the most commonly used formats for web images are JPEG, PNG and GIF. Here’s a breakdown of when to use each format:

  1. JPEG (Joint Photographic Experts Group): JPEG images are ideal for photographs and complex images with gradients. They offer high compression rates, allowing you to maintain a balance between image quality and file size. JPEG images can be cropped without significant loss of resolution however they do not support transparency.
  2. PNG (Portable Network Graphics): PNG images are best suited for images that require transparency, such as logos and icons. Unlike JPEG images, PNG images support lossless compression, meaning you can resize or crop them without losing any image quality. However, keep in mind that PNG images tend to have larger file sizes than JPEG images.
  3. GIF (Graphics Interchange Format): Gif images are best suited for simple forms of looping animated format. Although it is possible to have statci images a gif, this is not a great idea as they do not compress well. It has become fashionable to use large gif’s instead of video files on websites sometimes. However in many cases this is not a good idea as gif’s can’t be compressed as well as video files and you can’t prevent them from autoplaying or stop them from being loaded on page load, like videos.

Choose the file format that best suits your image type and optimise it accordingly to strike the right balance between image quality, file size and functionality.

Step 3: Use Descriptive Filenames and Alt Text

Naming your image files and providing descriptive alt text is crucial for both user experience and SEO. Search engines rely on text to understand and categoriae images, so make sure to follow these best practices:

  1. Descriptive Filenames: When saving your image files, use descriptive filenames that accurately reflect the content of the image. Avoid generic names like “image1.jpg” and instead use relevant keywords that describe the image. For example, if you’re selling a red dress, a suitable filename could be “red-dress-product-shot.jpg”.
  2. Alt Text: Alt text, or alternative text, is a text description that appears in place of an image when it fails to load. It serves as a valuable source of information for search engines and visually impaired users who rely on screen readers. Ensure that your alt text accurately describes the image content and includes relevant keywords. However, avoid keyword stuffing and prioritise providing meaningful and helpful descriptions. For a more detailed overview of best practices with alt text please read our article on the subject.

By using descriptive filenames and alt text, you provide search engines with valuable information about your images, improving their visibility in search results.

Step 4: Implement Image Structured Data

Structured data, also known as schema markup, helps search engines understand the context and content of your images. By implementing image-structured data, you can enhance the visibility of your images in search results and potentially achieve rich results such as image carousels or badges. Here are some key points to consider:

  1. Image Object Property: Use the ImageObject property to define the image on your webpage. Include relevant information such as the image URL, caption, and license details if applicable.
  2. Image Property: Utilise the image property to specify the main image associated with your webpage. This helps search engines accurately index and display the primary image in search results.
  3. Product Image Property: If you’re optimising images for eCommerce product pages, consider using the productImage property to indicate that the image represents a specific product. This can enhance the visibility of your products in search results, leading to higher click-through rates.

Implementing image-structured data requires technical knowledge and HTML markup. Consult your web developer or refer to Google’s Structured Data documentation for detailed instructions.

Step 5: Utilise Lazy Loading

Lazy loading is a technique that improves page load times by deferring the loading of images until they are needed. It helps reduce initial page load times and improves the overall user experience. When implementing lazy loading, follow these guidelines:

  1. Load Images on Scroll: Load images as users scroll down the page, ensuring that only the images visible within the viewport are loaded initially. As users continue scrolling, additional images are loaded dynamically.
  2. Responsive Lazy Loading: Implement responsive lazy loading to cater to users accessing your website from various devices. Adjust the lazy loading behaviour based on screen size and resolution to ensure optimal performance.

Lazy loading can be implemented using JavaScript libraries or plugins. Check if your content management system (CMS) or website builder offers built-in lazy loading functionality. Additionally, many third-party plugins and libraries are available to simplify the implementation process.

Step 6: Optimise Image Delivery with a Content Delivery Network (CDN)

A Content Delivery Network (CDN) is a network of servers distributed across various geographic locations. By leveraging a CDN, you can optimise image delivery by reducing latency and improving website performance. Here’s how a CDN can benefit your image SEO:

  1. Faster Image Loading: CDNs store your images on multiple servers worldwide. When a user accesses your website, the CDN delivers the image from the server closest to their location, reducing the time it takes for the image to load.
  2. Improved User Experience: With faster image loading times, your website visitors enjoy a smoother browsing experience. Reduced page load times and improved performance can lead to higher engagement and increased conversions.

To utilise a CDN for your image delivery, sign up with a reputable CDN provider like Cloudflare, Fastly, or Amazon CloudFront. Follow their documentation to configure your CDN and integrate it with your website.

Step 7: Monitor Image Performance

Continuously monitoring the performance of your optimised images is essential to ensure they’re contributing positively to your website’s SEO. Here are a few metrics to keep an eye on:

  1. Page Load Time: Regularly check your website’s page load times using tools like Google PageSpeed Insights or GTmetrix. Monitor the impact of image optimisation on your website’s overall performance.
  2. Image Size: Verify that your optimised images have reduced file sizes compared to their original versions. Keep track of the average image size across your website to ensure consistent optimisation.
  3. Search Engine Rankings: Monitor your search engine rankings for relevant keywords and track the visibility of your images in Google’s image search results. This will help you assess the effectiveness of your image SEO efforts.

By monitoring these metrics, you can identify any issues or areas for improvement and make necessary adjustments to further optimise your images for SEO.


Optimising images for SEO is crucial to enhancing your website’s visibility, improving page speed, and increasing organic traffic. By following the steps outlined in this comprehensive guide, you can ensure that your images are properly sized, formatted, and optimised for search engines. Remember to choose the right file format, use descriptive filenames and alt text, implement structured data, utilise lazy loading, leverage a CDN, and monitor image performance. With these best practices in place, you’ll be well on your way to achieving SEO-optimised images that drive better user engagement and higher search engine rankings.

Implement these image optimisation techniques today and watch your website soar to new heights in search engine rankings. Happy optimising!


Writen by Nick

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3.4 Keyword analysis to improve the organic SEO of your business