How to Optimize Images for Email Campaigns

An illustration of an email with optimized images avoiding a spam folder

You've crafted the perfect subject line, written compelling copy, and included a clear call-to-action. But if your email marketing campaign is full of large, heavy images, it might be dead on arrival. Heavy images can cause your emails to load slowly, display incorrectly, and, worst of all, get flagged as spam.

Optimizing the images in your emails is a critical step that many marketers overlook. It ensures a better user experience for your subscribers and dramatically increases the chances of your message landing in the inbox, not the junk folder.

How Large Images Can Hurt Your Email Campaigns

Best Practices for Email Image Optimization

The key is to keep your image file sizes as small as possible without turning them into a pixelated mess.

A Simple Workflow for Optimizing Email Images

You can easily optimize all your campaign images in minutes using a free online tool.

  1. Step 1: Finalize Your Images

    Gather all the images you plan to use in your email campaign.

  2. Step 2: Use an Online Resizer and Compressor

    Go to https://imageresizeronline.net/. You can upload multiple images at once to streamline your workflow.

  3. Step 3: Resize First

    For each image, enter the exact width you need for your email template (e.g., 600 pixels). Let the height adjust automatically to maintain the aspect ratio.

  4. Step 4: Compress for File Size

    Next, use the compression feature. Adjust the quality slider until you get a significantly smaller file size (aim for under 100 KB per image if possible) while the image still looks great in the preview.

  5. Step 5: Download and Insert

    Download your newly optimized images. They are now ready to be inserted into your email campaign platform (like Mailchimp, Klaviyo, etc.).

By taking these few extra minutes to optimize your images, you'll improve your email deliverability, increase engagement, and provide a better experience for your subscribers. Make it a standard part of your pre-launch checklist and watch your campaign metrics improve.