How to Optimise Images for the Web: A Step-by-Step Guide

Optimising images for the web is crucial for faster page loading times, better performance, and improved SEO. Large or unoptimised images can slow down your website, affecting both user experience and search engine rankings. This guide will show you how to resize, compress, and properly format images before uploading them to your website.

Step 1: Choose the Right Image Format

Selecting the correct image format is the first step in optimising images for the web. The most commonly used formats are:

1. JPEG: Best for photos or images with lots of colour variations.

   • Use JPEG for images where fine details aren’t critical, as it offers good compression with minimal quality loss.

2. PNG: Best for images with transparency or sharp edges, such as logos or icons.

   • PNG files are usually larger than JPEGs but maintain higher quality and support transparency.

3. WebP: A newer format that offers both lossless and lossy compression, providing smaller file sizes without sacrificing too much quality.

   • If supported by your website, WebP is ideal for optimal performance.

Step 2: Resize Images to the Correct Dimensions

Uploading images larger than needed wastes storage space and slows down your website. Resizing the images to the correct dimensions helps reduce the file size.

1. Determine the Required Size:

   • Consider where the image will be used on the website (e.g., full-screen banner, thumbnail, blog post).
   • Example:
     • Full-width banner: Resize to about 2048 pixels in width.
     • Blog post featured image: Resize to 2048 pixels in width.
     • Thumbnails: Resize to around 150-300 pixels in width.

2. Use an Image Editing Tool:

   • You can resize images using tools like:
     • Adobe Photoshop (Go to: Image > Image Size)
     • GIMP (Free software: Go to Image > Scale Image)
     • Online Tools:
       • Canva (Free: Resize option)
       • PicResize (Free online image resizer: www.picresize.com)
       • Fotor (Free online editor: www.fotor.com)

3. Save the Resized Image:

   • After resizing the image, save it in the appropriate format (JPEG, PNG, or WebP).

Step 3: Compress Images Without Losing Quality

Compression reduces the file size of an image without noticeable quality loss. This helps your website load faster while preserving visual integrity.

1. Use Image Compression Tools:

   • There are many tools available to compress images:
     • TinyPNG: Compresses PNG and JPEG images (www.tinypng.com).
     • ImageOptim: A free desktop tool for Mac that compresses images.
     • JPEG-Optimizer: An online JPEG image compressor (www.jpeg-optimizer.com).
     • Squoosh: A Google tool that lets you adjust compression levels and preview the result (squoosh.app).

2. Adjust Compression Settings:

   • Many tools allow you to choose the compression level. Aim for a balance between file size and quality.
   • For most photos, reducing the image quality to 70-80% works well.

3. Check the Compressed File Size:

   • The goal is to keep most images under 200KB. For larger images (e.g.,hero banners), aim for a maximum of 500KB.
   • You can further compress images if the file size is still too large.

Step 4: Optimise Image File Names for SEO

Giving your images descriptive and SEO-friendly file names can help search engines understand the content of your images and improve your rankings.

1. Rename Your Image Files:
   • Instead of using default names like IMG_1234.jpg, use descriptive file names.
   • Example: web-design-services-port-elizabeth.jpg.
2. Use Hyphens to Separate Words:
   • Google prefers hyphens (-) over underscores (_) when reading file names.
   • Example: product-image-large.png instead of product_image_large.png.

Step 5: Add Alt Text for Accessibility and SEO

Alt text (alternative text) describes your images for search engines and visually impaired users. It’s important for both SEO and accessibility.

1. Describe the Image:
   • In your website’s content management system (CMS) or when uploading images, you’ll see an option to add alt text.
   • Make the alt text descriptive, but keep it concise.
2. Incorporate Keywords:
   • Where relevant, include keywords related to the image and page content to improve SEO.
   • Example: For an image of a web design project, your alt text could be: Responsive web design for a Port Elizabeth business.

Step 6: Use Lazy Loading for Better Performance

Lazy loading is a technique that defers loading images until they are visible on the user’s screen. This helps improve page loading speeds, especially for pages with multiple images.

1. Enable Lazy Loading:

   • In WordPress, lazy loading is typically enabled by default (version 5.5 and above).
   • If it’s not enabled or you’re using another platform, you can install a plugin like Smush or Lazy Load by WP Rocket.

2. Verify Lazy Loading is Active:

   • You can test lazy loading by inspecting the website’s HTML code. Look for the loading="lazy" attribute on your image tags.

Step 7: Use a Content Delivery Network (CDN) for Faster Load Times

A Content Delivery Network (CDN) helps distribute your website’s content across multiple servers worldwide, allowing images to load faster for users, regardless of their location.

1. Sign Up for a CDN:
   • Popular CDNs include Cloudflare, KeyCDN, and StackPath.
2. Integrate the CDN with Your Website:
   • Most CDNs provide step-by-step instructions on integrating with your website. If you’re using WordPress, many CDN services have plugins that make integration easy.

Step 8: Test Your Optimised Images

Once you’ve resised, compressed, and uploaded your images, it’s important to test their performance to ensure your website is loading efficiently.

1. Use Google PageSpeed Insights:

   • Go to PageSpeed Insights and enter your website’s URL.
   • This tool will analyse your website’s performance and offer suggestions, including image optimisation improvements.

2. Use GTmetrix:

   • Visit GTmetrix to test how quickly your images load on your website. GTmetrix provides insights into what’s slowing down your site and offers optimisation tips.

Step 9: Upload Your Optimised Images

After resising and compressing your images, you can now upload them to your website:

1. Go to Your WordPress Dashboard:

   • Log into your website’s dashboard.

2. Navigate to the Media Library:

   • Click on Media > Add New to upload your optimised images.

3. Insert Images into Your Pages or Posts:

   • Once uploaded, you can add the images to your posts, product pages, or galleries by clicking Add Media in your WordPress editor.

Conclusion

By optimising images for the web, you can significantly improve your website’s speed, user experience, and SEO rankings. Follow these steps to resize, compress, and format your images correctly, and your website will benefit from faster load times and better overall performance.

This step-by-step guide will help you ensure that every image you upload is optimised for web performance, leading to better results in terms of both user experience and search engine visibility.