WhoTheHeckSentThis – Add Sender Pictures to Thunderbird Mail with Zero Setup

You open Thunderbird. Your inbox is a wall of names. “David Chen” — which David? “Newsletter@somethingcorp.com” — the one you signed up for, or the one that found you? You scroll. You squint. You question your choices.

WhoTheHeckSentThis puts a face — or at minimum a logo — next to every sender in your thread pane. Less time playing email CSI. More time reading your actual mail.

What It Does

WhoTheHeckSentThis resolves sender avatars automatically, working through a priority list you
 control:

• Address Book — if you’ve got a photo saved for a contact, it shows up. Fully local. No network required.
• Gravatar — pulls public profile photos from gravatar.com. Opt-in, off by default.
• DuckDuckGo Icons — company logos and domain icons via DuckDuckGo’s privacy-friendly CDN. Sends only the email domain. Off by default — the first-run setup screen recommends enabling this.
• Google Favicon Service — a secondary fallback for domains DDG doesn’t have. Opt-in, off by default. It’s Google. You know the deal.
• Generated Initials — if nothing else resolves, a clean color-coded initials avatar is generated entirely on your machine. Always last. Always there.

Everything resolves once, then caches locally. For most senders you’ll never hit the network twice.

Features

• Zero setup — install and go. Avatars start appearing in your thread pane immediately.
• Right-click to override — not satisfied with what got pulled automatically? Right-click any message → WhoTheHeckSentThis → Update Avatar Icon. Search the web, or upload an image directly.
• Three badge styles — Peeking (rotated, tucked behind the message row), Corner, or Watermark. Pick the one that fits how you work.                                                             
• Save to Address Book with avatar — one click saves the contact and embeds the resolved photo directly into the vCard.                                                                         
• Backup & restore — export your custom avatars and settings to a JSON file. Import them back anytime, on any machine.                                                                         
• All density modes — Compact, Normal, and Touch (Relaxed) all render correctly.
• Dark mode — settings follow your system preference.

Install

[Download on addons.thunderbird.net →][ATN_PLACEHOLDER]

Requires Thunderbird 115.10.0 (Supernova) or later. Free. No account required.

Privacy & Data Use

Here is exactly what WhoTheHeckSentThis does and does not do with your data. No legalese — just the facts.

What never leaves your machine:

• Your email content. The extension only ever sees a sender’s name and email address — never subject lines, message bodies, attachments, or anything else.
• Your address book data, beyond a lookup by the sender’s email address to find a matching photo.
• Generated initials avatars — computed locally from the sender’s name and email, never transmitted anywhere.
• Resolved avatars — once fetched, images are stored in your extension’s local storage on your own machine.
• The ‘full unrestricted access’ warning is standard for any Thunderbird add-on that modifies the      
   message list UI — it’s the only API available for that.
  

What may leave your machine

This depends entirely on which sources you have enabled in Settings → Avatar Sources.

A note on Gravatar: We send an MD5 hash rather than the raw email address. However, MD5 hashes of common email addresses can be reverse-looked up via publicly available rainbow tables. If that concerns you — leave Gravatar off. It’s off by default for exactly this reason.

No analytics. No telemetry. No server.

WhoTheHeckSentThis does not collect usage data, crash reports, or analytics of any kind. There is no server. There is no account. Jack Harvest cannot see anything about how you use this extension — because the extension never talks to Jack Harvest.

Going fully local?

Turn off all three external sources in Settings → Avatar Sources. With that done, the extension  
 runs entirely on your machine: Address Book photos and generated initials only. No network
 requests are made.

Credits & Open Source

• MD5 Implementation by Joseph Myers (http://www.myersdaily.org/joseph/javascript/md5-text.html) — bundled because Gravatar requires MD5 and the WebCrypto API doesn’t support it.
• Gravatar — avatar lookup service by Automattic (https://gravatar.com)
• DuckDuckGo — privacy-friendly icon CDN (https://duckduckgo.com)
• Google Favicon Service — fallback favicon CDN (https://google.com)

Support the Project

WhoTheHeckSentThis is free, and it’s staying that way.

If it’s saved you even five minutes of inbox squinting, buying Jack Harvest a coffee goes a long way:

[Support on Ko-fi →][KOFI_PLACEHOLDER]

For bugs, feature requests, or “this broke on my specific weird setup” — file a report on the ATN listing page or track down Jack Harvest online.

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Thunderbird deserved better. Now it has it.