How to Optimize Image-Heavy Emails for Perfect Rendering

Images can make your emails stand out, but sending emails filled only with images comes with a cost. If your image-heavy emails load slowly, break on mobile, or appear inconsistent across email clients, your open and click-through rates will suffer, and so will your campaign objective.

In this blog, we’ll walk you through how you can use simple optimization techniques to optimize image-heavy emails.

How to optimize image-heavy emails

Mailmodo provides a no-code email editor that makes it a breeze to optimize image-heavy emails. Here’s how you can do it:

1. Image size optimization

If uploading from your device, Mailmodo limits the image size to 1 MB. This automatically ensures that your image doesn’t become too heavy for the template. Some other best practices when picking images are:

• Banners and first-fold images should match your email width, usually 600–900px wide.

• Logos/headshots work well at around 64–100px, so they stay crisp but not oversized.

• Icons should be 50–100px wide for a clean, minimal look.

2. Add alt text

Alt text ensures your message gets across even if the images don’t load. In Mailmodo, you can add alt text under image options once you’ve added the image.

Tip: Keep it short, descriptive, and relevant. For example, “ Sale Banner - Up to 50% Off” works better than “Image1.jpg.”

3. Set the right aspect ratio

Keep the correct aspect ratio ensuring your images don’t look stretched, squished, or awkward in your email. In Mailmodo, you can choose from four common ratios for each image:

• Square: Perfect for logos, icons, or small product shots.

• Landscape: Ideal for banners, hero images, and wide visuals.

• Portrait: Works well for headshots or vertical product images.

• Panorama: Great for wide, cinematic banners that span across the email width.

Here, you can also define the size of the image to be displayed in terms of pixels, percentage, or set it on auto.

4. Adjust image border

Borders can make your images pop and improve overall readability, but it’s important to use them wisely.

In Mailmodo, you can:

• Choose a solid or dashed border

• Pick a border color that compliments your design

• Adjust the corner radius for square or rounded edges.

For best results, keep borders thin and consistent across similar images, and preview on mobile to ensure rounded corners or dashed styles render properly.

5. Fine-tune padding and alignment

Padding and alignment give your design breathing room. In Mailmodo, you can easily tweak horizontal alignment (left, center, right) and padding around the image for better-looking images.

6. Optimize for mobile display

Most people read emails on their phones, so making sure your images look great on mobile is essential. When optimizing for mobile display, you get two options for displaying your images:

1. Full width: This stretches your image to fill the width of the screen, perfect for hero banners or first-fold images that need maximum impact.

2. Scale down: If your image sits inside a column, choose the scale-down option. This keeps the image proportional and responsive.

Final thoughts

With Mailmodo, you can build beautiful, image-heavy emails that load fast, look great across devices, and stay within performance best practices, all without writing a single line of code (unless you want to).

Whether you're launching a product, showcasing a gallery, or creating a high-impact visual newsletter, Mailmodo equips you with everything you need to do it right.

Ready to level up your visual emails? Try optimizing your next campaign inside Mailmodo and your results will thank you.