Optimising Image Sizes for Emails: A Guide to Perfect Headers and More

Visuals play a crucial role in capturing attention in email marketing, conveying your messages effectively. However, using images incorrectly can lead to a poor user experience, slow load times, and even deliverability issues. Here's how to optimise image sizes for your emails, with a focus on headers and other key visual elements.

1. Why Image Size Matters in Emails

Load Time and Deliverability: Large images can slow down email load times, which can frustrate recipients and increase the likelihood of your emails being marked as spam.

User Experience: Properly sized images ensure that your emails look great across all devices and email clients, providing a consistent and professional appearance.

Responsive Design: Optimised images contribute to a responsive design, ensuring your emails are mobile-friendly and look good on any screen size.

2. Optimal Image Sizes for Different Email Elements

Header Images:

Width: Aim for 600-650 pixels wide. This width fits well within most email clients and provides a good balance between visual impact and load time.

Height: Typically, 100-200 pixels is sufficient, but this can vary based on your design. Avoid making headers too tall, as they can push important content below the fold.

Hero Images:

Width: Similar to header images, 600-650 pixels wide is ideal.

Height: 300-500 pixels. Hero images are usually larger and can be more dynamic, but ensure they're not so tall that they dominate the email.

Logos:

Width: Around 100-200 pixels. Logos should be visible and recognisable without overwhelming the rest of the content.

Height: Maintain the aspect ratio of your logo, but generally 50-100 pixels.

Content Images:

Width: For single-column layouts, stick to 600-650 pixels. For multi-column layouts, adjust accordingly (e.g., 300-400 pixels for a two-column design).

Height: Varies based on content, but aim for a height that maintains clarity without excessive scrolling.

Thumbnails:

Width: 150-200 pixels.

Height: Match the width to maintain a square or rectangular aspect ratio.

3. Best Practices for Email Images

Compression and Format:

- Use image formats that balance quality and file size. JPEGs are great for photographs, while PNGs work well for graphics with transparent backgrounds, but can often be larger in size.

- Compress images to reduce file size without compromising quality. Tools like TinyPNG or JPEG Optimizer can help.

Alt Text:

- Always include alt text for your images. This improves accessibility and ensures that your message is still conveyed if images don't load.

Responsive Design:

- if you can, use CSS media queries to adjust image sizes for different screen widths. Many email service providers offer built-in responsive design tools so these skills aren’t necessary.

Test Across Clients:

- Email clients handle images differently. Test your emails across various clients (Gmail, Outlook, Apple Mail, etc.) to ensure consistent display.

Avoid Image-Only Emails:

- While images are important, relying solely on images can trigger spam filters. Balance your emails with a mix of text and visuals.

4. Tools and Resources

- Canva: For designing email headers and graphics.

- Adobe Photoshop: Advanced editing and optimisation.

- Litmus: For testing emails across different clients.

- TinyPNG/JPEG Optimizer: For image compression.

Optimising image sizes in your emails is crucial for maintaining a professional appearance, ensuring fast load times, and improving deliverability. By following these guidelines for headers, logos, content images, and more, you can create visually appealing emails that engage your audience and convey your message effectively.

Do you have any tips for optimising email images? Share them in the comments below!