Allow external email images

External images can contact a sender-controlled server. MailGen offers two choices for blocked images:

• View once: allow images in the currently open body, including quoted history. Closing or replacing the body ends this permission.
• Trust sender: store the normalized sender email address. A display name alone cannot establish trust.

Trust applies across the signed-in app user's connected accounts. The current source is msintegrationv2.mailgen_user_settings.settings. Older deployments used betterauth.user.user_settings.trustedExternalImageSenders. See MailGen settings storage.

The server value controls initial load. Empty local settings cannot overwrite it. Ordinary display-setting saves and resets preserve trusted senders. Concurrent additions use an atomic database update.

Trust sender enables images only after an authenticated save succeeds. If saving fails, images remain blocked. The interface shows an error and a retry control.

Permission does not disable active-content filtering. Scripts, iframe, object, and embed elements remain removed. Before permission, MailGen also blocks img/picture sources, HTML backgrounds, inline CSS URLs, and stylesheet URL/import references. Attachment downloads use their separate flow.