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Unnamed repository; edit this file 'description' to name the repository. 

feat: use full-resolution download URL for og:image previews

Images now point to the original file instead of the 300px thumbnail,
giving Discord/Telegram the highest quality preview frame. For videos,
the thumbnail is kept as a static poster since the download is a video
file. The body image in the OG page uses the same URL.

Assisted-by: Crush:deepseek-v4-flash
Maxwell Jensen maxwelljensen@posteo.net
Thu, 14 May 2026 11:34:32 +0200
commit

fb3daf470ec0942e6de2372f28aeb79c53d22ed4

parent

0ba068faac3861b09c7dc896d508fa45e594e23e

2 files changed, 18 insertions(+), 3 deletions(-)

jump to
M internal/server/server.go → internal/server/server.go 
@@ -229,6 +229,14 @@ }
 
 	isVideo := strings.HasPrefix(img.MimeType, "video/")
 
+	// For images (including GIFs), use the full-resolution download URL as the
+	// og:image so platforms display a high-quality preview. For videos, use the
+	// thumbnail as a static poster frame since the download URL is a video file.
+	ogImageURL := thumbURL
+	if !isVideo {
+		ogImageURL = downloadURL
+	}
+
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
 
 	fmt.Fprintf(w, `<!DOCTYPE html>

@@ -254,9 +262,9 @@ `,
 		htmlEsc(title), htmlEsc(description),
 		htmlEsc(title), htmlEsc(description),
 		htmlEsc(pageURL),
-		htmlEsc(thumbURL), htmlEsc(thumbURL),
+		htmlEsc(ogImageURL), htmlEsc(ogImageURL),
 		img.Width, img.Height,
-		htmlEsc(title), htmlEsc(description), htmlEsc(thumbURL))
+		htmlEsc(title), htmlEsc(description), htmlEsc(ogImageURL))
 
 	if isVideo {
 		fmt.Fprintf(w, `<meta property="og:type" content="video">

@@ -292,7 +300,7 @@ </head>
 <body>
 <img src="%s" alt="%s" style="max-width:100%%">
 </body>
-</html>`, idStr, htmlEsc(thumbURL), htmlEsc(title))
+</html>`, idStr, htmlEsc(ogImageURL), htmlEsc(title))
 }
 
 func handleHealth(w http.ResponseWriter, r *http.Request) {
M internal/server/server_test.go → internal/server/server_test.go 
@@ -94,6 +94,13 @@ }
 	if !strings.Contains(html, "1920") {
 		t.Errorf("expected width in OG image:width, got:\n%s", html)
 	}
+	// For images, og:image should point to the download URL (full-res), not thumbnail.
+	if !strings.Contains(html, "/download") {
+		t.Errorf("expected og:image to use download URL (full-res) for images, got:\n%s", html)
+	}
+	if strings.Contains(html, "/thumbnail") {
+		t.Errorf("og:image should use download URL for images, not thumbnail:\n%s", html)
+	}
 	if strings.Contains(html, "&amp;") || strings.Contains(html, "&lt;") {
 		t.Errorf("HTML appears double-escaped:\n%s", html)
 	}