diff --git a/Libraries/LibWeb/Loader/Resource.cpp b/Libraries/LibWeb/Loader/Resource.cpp
index 48eb4439913..905339c5e9b 100644
--- a/Libraries/LibWeb/Loader/Resource.cpp
+++ b/Libraries/LibWeb/Loader/Resource.cpp
@@ -79,6 +79,8 @@ String mime_type_from_content_type(const String& content_type)
 
 static String guess_mime_type_based_on_filename(const URL& url)
 {
+    if (url.path().ends_with(".pbm"))
+        return "image/x‑portable‑bitmap";
     if (url.path().ends_with(".png"))
         return "image/png";
     if (url.path().ends_with(".gif"))