Title: Outlook displays header and footer images as attachments in HTML email
Description:
We are generating HTML email content in OutSystems using TinyMCE. The HTML contains header and footer images referenced through absolute HTTPS URLs:
The HTML is passed through the following flow:
TinyMCE HTML→ MoveCssInlineHTML→ SanitizeHtml(P_Content)→ Email Screen→ Custom SendEmail Server Action→ Outlook
The final HTML contains only external image URLs and does not use cid: or Base64 images.
Issue:
Outlook may display externally referenced images as attachments when the email content is processed or modified during sanitization or sending. Even though the images are loaded using HTTPS URLs, Outlook can still treat them as inline resources if certain email headers or MIME settings are applied by the custom SendEmail implementation. To resolve this, ensure the email is sent as pure HTML without embedding images as linked resources or attachments, verify that the Content-Disposition is not set to inline or attachment for images, and avoid any email processing logic that converts external image URLs into embedded resources during the SendEmail flow.
but we need header and footer in email and this is a image so how can we send html