diff --git a/docs/src/content/docs/changelog.md b/docs/src/content/docs/changelog.md
index 5026a602..ef2f78b6 100644
--- a/docs/src/content/docs/changelog.md
+++ b/docs/src/content/docs/changelog.md
@@ -22,6 +22,9 @@ Requires libvips v8.16.1
   [#4387](https://github.com/lovell/sharp/pull/4387)
   [@Stephen-X](https://github.com/Stephen-X)
 
+* Ensure support for wide-character filenames on Windows (regression in 0.34.0).
+  [#4391](https://github.com/lovell/sharp/issues/4391)
+
 ### v0.34.1 - 7th April 2025
 
 * TypeScript: Ensure new `autoOrient` property is optional.
diff --git a/src/pipeline.cc b/src/pipeline.cc
index 21529acf..bb12a400 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -1359,7 +1359,8 @@ class PipelineWorker : public Napi::AsyncWorker {
         // Add file size to info
         if (baton->formatOut != "dz" || sharp::IsDzZip(baton->fileOut)) {
           try {
-            uint32_t const size = static_cast<uint32_t>(std::filesystem::file_size(baton->fileOut));
+            uint32_t const size = static_cast<uint32_t>(
+              std::filesystem::file_size(std::filesystem::u8path(baton->fileOut)));
             info.Set("size", size);
           } catch (...) {}
         }
diff --git a/test/unit/io.js b/test/unit/io.js
index 98b96a57..038bfe1f 100644
--- a/test/unit/io.js
+++ b/test/unit/io.js
@@ -1036,4 +1036,21 @@ describe('Input/output', function () {
       });
     readable.pipe(inPipeline).pipe(badPipeline);
   });
+
+  it('supports wide-character filenames', async () => {
+    const filename = fixtures.path('output.图片.jpg');
+    const create = {
+      width: 8,
+      height: 8,
+      channels: 3,
+      background: 'green'
+    };
+    await sharp({ create }).toFile(filename);
+
+    const { width, height, channels, format } = await sharp(filename).metadata();
+    assert.strictEqual(width, 8);
+    assert.strictEqual(height, 8);
+    assert.strictEqual(channels, 3);
+    assert.strictEqual(format, 'jpeg');
+  });
 });