Embed Images

When rendering rich emails with images, you can either host images on a public CDN or embed them directly via Content-ID (cid:).

Method 1: Hosted Images (Recommended)

Host your images on an HTTPS CDN (e.g. AWS S3, Cloudflare R2, Vercel Blob) and link them using standard HTML <img> tags:

<img src="https://assets.yourcompany.com/logo.png" alt="Company Logo" width="120" />

Method 2: Inline CID Attachments

Attach the image file and assign it a unique content_id. You can then reference it directly in your HTML:

await mailofly.emails.send({
  from: "notifications@yourdomain.com",
  to: ["user@example.com"],
  subject: "Receipt",
  html: `<p>Your receipt:</p><img src="cid:receipt-header" />`,
  attachments: [
    {
      filename: "header.png",
      content: base64Buffer,
      content_id: "receipt-header"
    }
  ]
});

Related topics

Attachments Tracking Broadcast editor Template Editor Introduction

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