How to Optimise Images for Faster WordPress Websites

Optimising images on your WordPress site is one of the best ways to improve performance, making pages load faster and providing a better user experience. Proper image sizing and compression reduce page load times, improve SEO, and help create a smooth browsing experience. In this post, we’ll walk you through optimising your images—explaining why image size and format matter and giving you simple, practical steps to make your WordPress site run faster.

1. Sizing Images Correctly for Web Use

When it comes to images on the web, size matters. Uploading large images when they’re only going to be displayed in smaller sections of your site can lead to slow load times and wasted server resources. Here’s how to choose the right size for each image.

Why Image Dimensions Matter

Each image has a set of “physical dimensions”—the width and height of the image in pixels. When your website displays an image that’s larger than needed, it ends up resizing it on the fly. This extra resizing work requires more browser power and time, leading to longer load times.

How to Choose the Right Image Size

1. Consider the display area: Each section of your website has its own display dimensions. For example:
   • If you’re displaying an image in a two-column layout where each column is 500–700 pixels wide, you should size the image within this range.
   • For mobile display, you’ll typically need a maximum width of around 768–1024 pixels.
   By keeping the image’s width close to the actual display size, you avoid loading larger-than-needed files, keeping your site efficient.
2. Get familiar with your website layout: Different themes and layouts have unique requirements. Your website might automatically resize images, but uploading the right dimensions to begin with will save load time and server space.

Example

If you have a hero image meant for desktop screens, and it’s displayed at 1200 pixels wide, resize it to 1200 pixels before uploading. Similarly, a smaller blog image that displays at 600 pixels should be sized accordingly to reduce the file size.

2. Saving Images in Next-Gen Formats

New image formats like WebP and AVIF offer better compression than traditional JPEG or PNG formats. Using these next-gen formats reduces file sizes without sacrificing quality.

• WebP: Supported by most modern browsers, WebP files are smaller than JPEG and PNG files and retain high quality.
• AVIF: Provides even higher compression than WebP, but isn’t yet universally supported. For most WordPress users, WebP is the best balance between quality, compatibility, and size.

Tools for Saving in Next-Gen Formats

1. Online Converters:
   • Use free tools like Squoosh (https://squoosh.app/) and TinyPNG (https://tinypng.com/) to convert images to WebP format.
2. Image Editing Software:
   • GIMP: Open your image in GIMP, go to “File” > “Export As…” and choose WebP. Adjust the quality slider to find the right balance between file size and image quality.
   • Photoshop: Use the WebP plugin for Photoshop or convert images to WebP directly through “File” > “Export” > “Save for Web (Legacy).”
3. WordPress Plugins:
   • Plugins like Imagify or ShortPixel can automatically convert your images to WebP and compress them on upload. Many of these plugins include free versions that are excellent for basic optimisation needs.

3. Compressing Images to Save File Size

After setting the correct dimensions and format, compressing your images reduces file sizes without affecting visual quality.

Manual Compression

If you prefer a hands-on approach, compressing each image individually gives you the most control over quality.

• Online Compression: Websites like TinyPNG (for PNG and JPEG files) and Squoosh let you upload images and adjust compression levels.
• GIMP and Photoshop:
  • In GIMP: Use “Export As” and adjust the “Quality” slider for JPEG files. With WebP, try a quality of around 80–90% for a good balance.
  • In Photoshop: Select “Save for Web (Legacy)” and adjust quality sliders to reduce file size without losing too much quality.

Automated Compression

For websites with a lot of images, manual optimisation can be a time-consuming task. Automation tools in WordPress can help:

• Image Optimisation Plugins: Plugins like Smush, Imagify, or ShortPixel can automatically compress images as you upload them. Most plugins also offer bulk compression features to optimise your entire image library with one click.

When to Optimise Images Manually

Automation is helpful, but for crucial images—like product images in eCommerce stores—manual optimisation is worth the effort. Manually resized, formatted, and compressed images are usually smaller and clearer than automatically processed ones, helping to keep your site fast while presenting the best possible visuals to your users.

Key Takeaways

• Resize: Choose dimensions that fit the display area on your website, saving server resources and load time.
• Format: Use next-gen formats like WebP for better compression without sacrificing quality.
• Compress: Use tools to reduce file size before upload, and consider automated plugins for large libraries.

By following these steps, you’ll make your WordPress site faster, easier to navigate, and more user-friendly.

Still need help?

Still need help to optimise your WordPress site for speed? I offer a free website performance report to identify key areas for improvement and give you a clear plan to boost your site’s performance. Get in touch to learn how we can make your website faster and more efficient!