From 560ea8f0d6d8e8477349aeaac42544b11b9bc39c Mon Sep 17 00:00:00 2001
From: Ruben Hensen <ruben.hensen@protonmail.com>
Date: Thu, 4 Jun 2026 13:23:53 +0200
Subject: [PATCH 1/2] feat(email): replace unicode checkmark with inline PNG
 image

The signer-verified circle previously rendered a unicode `&#10003;`
glyph which is styled inconsistently across mail clients. Embed a
PNG of the PostGuard checkmark via `cid:pg-check` to match the
shape used in the download page UI.
---
 src/email.rs               |  10 +++++++++-
 templates/email/check.png  | Bin 0 -> 3170 bytes
 templates/email/email.html |   4 +++-
 3 files changed, 12 insertions(+), 2 deletions(-)
 create mode 100644 templates/email/check.png

diff --git a/src/email.rs b/src/email.rs
index 5cbfea5..1809dce 100644
--- a/src/email.rs
+++ b/src/email.rs
@@ -109,6 +109,11 @@ fn take_firstname_lastname_pair(attrs: &mut Vec<(String, String)>) -> Option<Str
 /// HTML-only-plus-remote-image spam signal flagged in postguard#197.
 const LOGO_PNG: &[u8] = include_bytes!("../templates/email/pg_logo.png");
 
+/// Inline checkmark glyph used inside the signer-verified circle in the
+/// HTML email, referenced via `cid:pg-check`. Replaces the previous
+/// unicode `&#10003;` so the mark renders consistently across clients.
+const CHECK_PNG: &[u8] = include_bytes!("../templates/email/check.png");
+
 use serde::{Deserialize, Serialize};
 use url::Url;
 
@@ -207,10 +212,13 @@ struct EmailTextTemplate<'a> {
 fn build_body(html: String, text: String) -> Result<MultiPart, Box<dyn std::error::Error>> {
     let logo = Attachment::new_inline("pg-logo".to_string())
         .body(LOGO_PNG.to_vec(), "image/png".parse::<ContentType>()?);
+    let check = Attachment::new_inline("pg-check".to_string())
+        .body(CHECK_PNG.to_vec(), "image/png".parse::<ContentType>()?);
 
     let related = MultiPart::related()
         .singlepart(SinglePart::html(html))
-        .singlepart(logo);
+        .singlepart(logo)
+        .singlepart(check);
 
     Ok(MultiPart::alternative()
         .singlepart(SinglePart::plain(text))
diff --git a/templates/email/check.png b/templates/email/check.png
new file mode 100644
index 0000000000000000000000000000000000000000..8e107dadee3caf71fd713292d0f0136f3953d432
GIT binary patch
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diff --git a/templates/email/email.html b/templates/email/email.html
index 3859648..194a53e 100644
--- a/templates/email/email.html
+++ b/templates/email/email.html
@@ -42,7 +42,9 @@
                 {% if sender_email != "" %}
                 <div style="margin-top:40px;padding-top:30px;border-top:1px solid #C6E2F6;text-align:center;">
                     <div style="margin-bottom:12px;">
-                        <span style="display:inline-block;width:32px;height:32px;line-height:32px;border-radius:50%;border:2px solid #5F7381;text-align:center;font-size:16px;color:#5F7381;box-sizing:border-box;">&#10003;</span>
+                        <span style="display:inline-block;width:32px;height:32px;line-height:32px;border-radius:50%;border:2px solid #5F7381;text-align:center;box-sizing:border-box;">
+                            <img src="cid:pg-check" alt="" width="16" height="13" style="display:inline-block;vertical-align:middle;" />
+                        </span>
                     </div>
                     <p style="font-size:13px;color:#5F7381;margin:0 0 6px 0;">{{files_from}}</p>
                     <p style="font-size:15px;font-weight:700;color:#030E17;margin:0 0 12px 0;">{{sender_email}}</p>

From d2962609af5da074d0deb6aa277e65459128aa59 Mon Sep 17 00:00:00 2001
From: Ruben Hensen <ruben.hensen@protonmail.com>
Date: Thu, 4 Jun 2026 15:39:00 +0200
Subject: [PATCH 2/2] feat(email): remove circle around signer-verified
 checkmark

---
 src/email.rs               | 2 +-
 templates/email/email.html | 4 +---
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/email.rs b/src/email.rs
index 1809dce..fd86a94 100644
--- a/src/email.rs
+++ b/src/email.rs
@@ -109,7 +109,7 @@ fn take_firstname_lastname_pair(attrs: &mut Vec<(String, String)>) -> Option<Str
 /// HTML-only-plus-remote-image spam signal flagged in postguard#197.
 const LOGO_PNG: &[u8] = include_bytes!("../templates/email/pg_logo.png");
 
-/// Inline checkmark glyph used inside the signer-verified circle in the
+/// Inline checkmark glyph shown next to the signer-verified email in the
 /// HTML email, referenced via `cid:pg-check`. Replaces the previous
 /// unicode `&#10003;` so the mark renders consistently across clients.
 const CHECK_PNG: &[u8] = include_bytes!("../templates/email/check.png");
diff --git a/templates/email/email.html b/templates/email/email.html
index 194a53e..0a0c87a 100644
--- a/templates/email/email.html
+++ b/templates/email/email.html
@@ -42,9 +42,7 @@
                 {% if sender_email != "" %}
                 <div style="margin-top:40px;padding-top:30px;border-top:1px solid #C6E2F6;text-align:center;">
                     <div style="margin-bottom:12px;">
-                        <span style="display:inline-block;width:32px;height:32px;line-height:32px;border-radius:50%;border:2px solid #5F7381;text-align:center;box-sizing:border-box;">
-                            <img src="cid:pg-check" alt="" width="16" height="13" style="display:inline-block;vertical-align:middle;" />
-                        </span>
+                        <img src="cid:pg-check" alt="" width="16" height="13" style="display:inline-block;vertical-align:middle;" />
                     </div>
                     <p style="font-size:13px;color:#5F7381;margin:0 0 6px 0;">{{files_from}}</p>
                     <p style="font-size:15px;font-weight:700;color:#030E17;margin:0 0 12px 0;">{{sender_email}}</p>