Images play a crucial role in website design, enhancing user experience and engagement. However, unoptimised images can slow down your site, negatively impacting SEO and usability.
Properly optimising images ensures your website loads quickly, improves accessibility, and ranks better in search engines.
Contents
- Why is Image Optimisation Important?
- Guide to Optimising Images for Websites
- FAQs for Optimising Images
Why is Image Optimisation Important?
Optimising images is essential for several reasons:
- Faster load times: Large, uncompressed images can slow down your website, leading to poor user experience and higher bounce rates.
- Better SEO: Optimised images contribute to good Core Web Vitals – search engines prioritise fast-loading websites, and optimised images are quicker to load.
- Improved user experience: Visitors expect smooth browsing, and fast-loading images enhance usability.
- Accessibility & compliance: Adding proper alt text makes images accessible to visually impaired users and improves website compliance with accessibility guidelines.
Guide to Optimising Images for Websites
1. Image Dimensions
Choosing the right image dimensions ensures your site loads efficiently without unnecessary bulk.
- Banner images: Max width of 1920 pixels, ideal for full-width display.
- Standard images: Max width of 800 pixels, suitable for most inline images.
- Thumbnails: Max width of 150-300 pixels, depending on usage.
2. Choose the Right File Format
Selecting the correct file format helps balance quality and file size.
- JPEG: Best for photographs due to high-quality compression.
- PNG: Use for graphics, logos, or images requiring transparency.
- WebP: Ideal for modern browsers, offering better compression without losing quality.
- SVG: Best for vector graphics like icons and logos (scalable without losing quality).
3. Resize Images
Resizing ensures images are not larger than needed, improving page speed. Use tools like:
- Photoshop: Use “Export As” for precise control over size and quality.
- Online tools: ResizeImage.net or PicResize for quick, easy resizing.
4. Compress Images
Compression reduces file size without noticeable quality loss.
- Online compression tools
- TinyPNG
- Squoosh
- Optimizilla
- WordPress plugins
- Smush
- ShortPixel
- EWWW Image Optimizer
5. Optimise File Naming
A clear, keyword-rich file name improves SEO.
Example: Instead of ‘IMG1234.jpg’, use ‘beach-sunset-holiday.jpg’ to make the image more discoverable.
6. Add Alt Text
Alt text improves SEO by describing the image content. It also helps accessibility as the image alt is read by screen readers.
Example: “A sunset over a beach with palm trees.”
7. Test Image Optimisation
Once images are optimised, test their performance using:
- Google PageSpeed Insights: Checks for oversized images and performance issues.
- GTmetrix: Identifies uncompressed images affecting site speed.
FAQs for Optimising Images
What’s the best image format for websites?
JPEG is ideal for photos, PNG for graphics, WebP for modern browsers, and SVG for scalable vector graphics.
How do I reduce image size without losing quality?
Use compression tools like TinyPNG or Squoosh to shrink file size while preserving image clarity.
Does image size affect SEO?
Yes, large images slow down your website, which can negatively impact search rankings.
What is alt text, and why is it important?
Alt text describes an image for screen readers and search engines, improving accessibility and SEO.
How often should I test my website’s images?
Regularly check images using Google PageSpeed Insights or GTmetrix to ensure they are properly optimised.