diff --git a/Cargo.toml b/Cargo.toml
index 5c24e963..5a71b928 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -70,3 +70,5 @@ name = "oxipng"
 path = "src/lib.rs"
 [profile.dev]
 opt-level = 2
+[profile.release]
+lto = true
diff --git a/tests/files/issue-171.png b/tests/files/issue-171.png
new file mode 100644
index 00000000..bf83f52b
Binary files /dev/null and b/tests/files/issue-171.png differ
diff --git a/tests/regression.rs b/tests/regression.rs
index a8dbe045..1b20edee 100644
--- a/tests/regression.rs
+++ b/tests/regression.rs
@@ -600,6 +600,7 @@ fn issue_159() {
 }
 
 #[test]
+#[cfg(target_pointer_width = "64")]
 fn issue_167() {
     test_it_converts(
         "tests/files/issue-167.png",
@@ -610,3 +611,15 @@ fn issue_167() {
         BitDepth::Eight,
     );
 }
+
+#[test]
+fn issue_171() {
+    test_it_converts(
+        "tests/files/issue-171.png",
+        None,
+        ColorType::Grayscale,
+        BitDepth::Eight,
+        ColorType::Grayscale,
+        BitDepth::Eight,
+    );
+}