Best Practice Guide to Using Images for WordPress Websites
Images are essential to modern web design. They enhance visual appeal, improve user engagement and, when optimised correctly, boost your website’s SEO performance. This guide outlines the best practices for using images on WordPress websites, covering everything from image formats and resizing to accessibility and SEO optimisation.
1. Choose the Right Image Format
Different image formats serve different purposes. Using the correct format can improve load times and display quality.
JPEG or JPG: Ideal for photographs and images with gradients. Offers good compression without sacrificing much quality.
PNG: Best for images requiring transparency or sharp detail, such as logos and icons. Larger file size than JPEG.
WebP: A modern format offering superior compression and quality. Supported by most modern browsers and WordPress from version 5.8 onwards.
SVG: Suitable for vector graphics like logos and icons. Small file size and scalable without losing quality. Use with care and ensure security when uploading SVGs to WordPress.
2. Resize and Optimise Image Dimensions
Why Resize Images?
Uploading large images slows down your website, increasing bounce rates and negatively impacting SEO.
Best Practices:
Resize images to the maximum dimensions needed before uploading. For example:
Blog post images: 1200px wide
Thumbnails: 150 × 150px
Full-width headers: 1920px wide
Use image editing tools like Snagit, IrfanView, or online tools such as TinyPNG, Squoosh or ImageOptim before uploading.
WordPress generates multiple image sizes automatically, including thumbnail, medium and large, but define custom sizes in your theme if necessary.
Use plugins like ShortPixel or EWWW Image Optimizer to compress images automatically.
3. Name Your Image Files Properly
Search engines read image file names, so naming them appropriately can improve image SEO.
Best Practices:
Use descriptive, keyword-rich file names.
Separate words with hyphens rather than underscores.
Avoid default camera file names like IMG_1234.jpg.
Example:
Bad: IMG_20250819.jpg
Good: sunset-over-isle-martin.jpg
4. Use Descriptive ALT Text for Accessibility and SEO
What is ALT Text?
ALT, or alternative, text describes an image’s content for screen readers and displays when an image fails to load.
Benefits:
Accessibility: Helps visually impaired users understand image content.
SEO: ALT text helps search engines understand and index images.
Best Practices:
Be accurate and descriptive.
Include relevant keywords where appropriate, but avoid keyword stuffing.
Do not include phrases such as “image of” or “picture of”, as this is already implied.
Example:
ALT text: “Local fisherman repairing nets on Isle Martin beach at sunset”
5. Use Captions and Image Titles Where Appropriate
Captions appear beneath the image and are useful for context or attribution.
Image titles appear as a tooltip when a user hovers over the image, although they are not always essential.
Captions can improve engagement, especially for historical or informative content. However, overuse can distract from your main content.
6. Enable Lazy Loading
What is Lazy Loading?
Lazy loading defers the loading of images until they are needed, for example when the user scrolls to them, reducing initial page load time.
Implementation:
WordPress has built-in lazy loading for images since version 5.5.
For older themes or advanced customisation, use plugins such as a3 Lazy Load or WP Rocket.
7. Use a CDN (Content Delivery Network)
A CDN stores images on servers around the world to serve them faster to users, regardless of their location.
Recommended CDNs:
Cloudflare
Jetpack (Site Accelerator)
Bunny.net
KeyCDN
A CDN significantly boosts load speeds for media-heavy sites.
8. Ensure Mobile Responsiveness
Why It Matters:
A large proportion of web traffic comes from mobile devices. Your images must display correctly on all screen sizes.
Tips:
Use responsive image settings in WordPress. The srcset and sizes attributes are added automatically.
Choose themes that are fully responsive and mobile-optimised.
Use percentage-based widths, such as width: 100%, in your CSS where custom layouts are used.
9. Avoid Using Text Inside Images for Important Content
Text embedded within images is not readable by screen readers or search engines.
Alternatives:
Use HTML and CSS for important textual content.
If you must use text in an image, for example in a poster or graphic, repeat the information in ALT text or the surrounding content.
10. Use Image Sitemaps for SEO (Optional but Beneficial)
Google can index images more effectively if they are listed in an image sitemap.
Implementation:
Use SEO plugins such as Yoast SEO or All in One SEO, which can automatically generate image sitemaps.
11. Keep the Media Library Organised
A tidy Media Library makes managing images easier in the long term.
Best Practices:
Use plugins like FileBird or Media Library Folders to organise media into folders or categories.
Delete unused images to reduce clutter and save hosting space.
12. Always Credit Image Sources (If Required)
If you are using stock photos, Creative Commons images or content from others, provide proper attribution unless you own full rights.
Best Practices:
Read licensing terms carefully.
Use free, high-quality image sources such as:
Unsplash
Pexels
Pixabay
Include credits in captions or at the end of your post if required.
13. Test Image Performance
Tools to Use:
Google PageSpeed Insights
GTmetrix
Lighthouse (in Chrome DevTools)
These tools highlight image issues affecting site speed or performance.
Conclusion
Using images effectively on a WordPress site is about more than aesthetics. Proper image optimisation improves page load speed, accessibility, user experience and SEO. By following these best practices, including resizing images, adding accurate ALT text, choosing the right formats and maintaining an organised Media Library, you ensure that your website is both visually compelling and technically sound.
FAQs
What size should images be for WordPress?
It depends on their use. Blog images should be around 1200px wide. Avoid uploading images larger than 2000px unless necessary for full-screen headers or galleries.
How many images are too many on a WordPress page?
There is no fixed limit, but ensure images are optimised and lazy-loaded. Too many uncompressed images will slow your site significantly.
Can images improve SEO?
Yes. Proper file naming, ALT text and compression can boost page rankings and improve visibility in Google Images.
