diff --git a/lib/src/darwin/native.dart b/lib/src/darwin/native.dart
index a96429c..a68e864 100644
--- a/lib/src/darwin/native.dart
+++ b/lib/src/darwin/native.dart
@@ -346,13 +346,14 @@ final class ImageConverterDarwin implements ImageConverterPlatform {
       final values = arena<Pointer<Void>>(3);
 
       // kCGImageSourceCreateThumbnailFromImageIfAbsent = kCFBooleanTrue
+      // Use 1.toNSNumber() — bool has no toNSNumber() extension; NSNumber(1) = YES.
       keys[0] = kCGImageSourceCreateThumbnailFromImageIfAbsent.cast();
-      values[0] = true.toNSNumber().ref.retainAndAutorelease().cast();
+      values[0] = 1.toNSNumber().ref.retainAndAutorelease().cast();
 
       // kCGImageSourceCreateThumbnailWithTransform = kCFBooleanTrue
       // This is the key that bakes the EXIF rotation into pixel data.
       keys[1] = kCGImageSourceCreateThumbnailWithTransform.cast();
-      values[1] = true.toNSNumber().ref.retainAndAutorelease().cast();
+      values[1] = 1.toNSNumber().ref.retainAndAutorelease().cast();
 
       // kCGImageSourceThumbnailMaxPixelSize = longest source edge
       // Setting this to the source's longest edge returns full resolution.