Detailed Guide to WordPress Image Sizes: Best Practices & Tips

Images are crucial for any website, and WordPress makes it easy to upload, display, and manage them. However, understanding how WordPress handles images, as well as the best sizes and formats to use, can significantly affect your website’s performance, speed, and user experience. In this guide, we’ll cover everything you need to know about WordPress image sizes, including optimising images, changing default sizes, using plugins, and ensuring that your images help rather than hinder your website.

 

Table of Contents

illustration of editing an image on a tablet device

WordPress Image Sizes Overview

WordPress automatically generates multiple versions of each image you upload. These sizes are important because they ensure that your images fit various parts of your website, such as galleries, headers, or blog posts, without compromising performance. By default, WordPress creates the following image sizes when you upload a new image:

  • Thumbnail: 150×150 pixels.
  • Medium: 300×300 pixels.
  • Large: 1024×1024 pixels.
  • Full Size: The original dimensions of the uploaded image.

WordPress uses these sizes to determine which one is appropriate for various locations on your website. For example, a blog post might display the “Medium” size image, while a gallery might use the “Thumbnail” size.

image editing

Recommended Image Sizes for WordPress

Knowing the right image size for each section of your website is essential for maintaining performance and visual appeal. Here are some common recommended image sizes for different sections of your WordPress site:

  • Blog Post Images: 1200×630 pixels (perfect for social media sharing as well).
  • Header Image: 1600×1080 pixels.
  • WooCommerce Product Images: 600×600 pixels (minimum for clarity, depending on theme settings).
  • Hero Image: 1600×1400 pixels (large images for landing pages or key content areas).
  • Gallery Images: 800×800 pixels (for a neat, responsive grid).
  • Featured Images: 400×300 pixels (standard for most themes).

These dimensions ensure that your images look great without unnecessarily large files that can slow down your website.

Choosing the Right Image Format (JPEG, PNG, GIF, WebP, etc.)

Choosing the correct image format is crucial for balancing quality and file size. Here’s an overview of the most common image formats in WordPress:

  • JPEG (Joint Photographic Experts Group): Best for photographs or images with many colours and gradients. JPEGs are compressed, which reduces file size while maintaining good quality.

  • PNG (Portable Network Graphics): Ideal for images requiring transparency or graphics with sharp lines, such as logos or icons. However, PNG files are larger in size compared to JPEGs.

  • GIF (Graphics Interchange Format): Commonly used for simple animations or low-resolution images. GIF files are limited to 256 colours, which makes them unsuitable for high-quality photos.

  • WebP: A modern image format that provides superior compression, resulting in smaller file sizes without sacrificing quality. WebP is supported by most browsers and is becoming increasingly popular for image optimisation.

Each format serves a different purpose, and choosing the right one will depend on your image content.

Plugins for WordPress Image Sizes

Several plugins are available to help you manage, optimise, and resize images in WordPress. These plugins can automatically compress images, change default image sizes, and even convert images to WebP for faster loading. Here are some popular plugins for managing image sizes in WordPress:

  1. Smush: Automatically compresses and resizes images, with the option to bulk optimize existing images.
  2. Imagify: Offers image compression, resizing, and WebP conversion in one tool.
  3. ShortPixel: Provides high-quality compression with options for lossy and lossless modes.
  4. Regenerate Thumbnails: Allows you to regenerate image thumbnails when you change image size settings.

These plugins are great for improving image load times and overall site performance.

Changing Default Image Sizes on WordPress

By default, WordPress generates three image sizes: Thumbnail, Medium, and Large. However, you can change these default sizes in the WordPress dashboard:

  1. Go to Settings > Media.
  2. Change the values for Thumbnail size, Medium size, and Large size according to your needs.
  3. Save changes.

For more customisation, you may need to use plugins or add custom code. This step is useful if your theme or content requires specific dimensions.

Adding Custom Image Sizes to WordPress

If you need a specific image size not covered by the default options, WordPress allows you to add custom image sizes using code. You can do this by adding the following snippet to your functions.php file:

php
add_image_size( 'custom-size', 800, 600, true ); // 800x600px, cropped

This code snippet adds a custom image size called “custom-size” that WordPress will generate whenever you upload a new image. You can then use this size in your templates with the_post_thumbnail('custom-size');.

How WordPress Manages the Images You Upload

When you upload an image to WordPress, it is automatically stored in the wp-content/uploads folder in your website’s root directory. WordPress then creates multiple sizes of that image (depending on your settings and plugins). These sizes are stored in subfolders within the uploads directory, organised by year and month.

Where and How WordPress Stores Your Images?

As mentioned, WordPress stores all uploaded images in the wp-content/uploads folder. For example, if you upload an image in December 2024, it might be stored in:

wp-content/uploads/2024/12/your-image.jpg

This organisation ensures that your files are easy to find and manage as your website grows.

What Are the Default WordPress Image Sizes?

WordPress generates four default image sizes when you upload an image:

  • Thumbnail: 150×150 pixels.
  • Medium: 300×300 pixels.
  • Large: 1024×1024 pixels.
  • Full Size: The image’s original size.

You can adjust these sizes in the Settings > Media section of your WordPress dashboard.

What’s the Ideal WordPress Header Image Size?

A typical header image should be around 1920×1080 pixels. This size works well for full-width headers and ensures that the image looks sharp on larger screens. However, depending on your theme, you might need to adjust this size to fit the design perfectly.

How to Change Default Image Sizes (and When You’d Need To)

If your theme or content requires different image sizes, you can change the default sizes via the Settings > Media section. Additionally, you may want to change the image sizes if you’re working on an eCommerce website (WooCommerce) or need specific sizes for mobile responsiveness.

WordPress Image File Sizes Optimisation

To optimise image file sizes, consider using:

  • Compression: Reducing image file sizes while preserving quality.
  • Formats: Use WebP or JPEG for photos, PNG for logos and icons, and consider GIF for animations.

Resizing & Responsive Images

Responsive images are crucial for mobile users. WordPress automatically handles this by including the srcset attribute in images, allowing browsers to select the best image size based on the user’s device.

WordPress Image SEO

Image SEO is just as important as text SEO. Here’s how to optimise your images for better search engine rankings:

  • Title Tags: Use descriptive, keyword-rich titles for your images.
  • Alt Tags: Write concise, informative alt text that describes the image and includes relevant keywords.

Final Word

Managing WordPress image sizes is essential for maintaining optimal website performance, SEO, and user experience. By selecting the right image sizes, optimising file formats, and using the best plugins for image compression, you can significantly improve your site’s speed and load times. Don’t forget about SEO and always optimise your images for search engines, helping them rank better in image searches.