diff --git a/packages/image-io/typescript/src/index.ts b/packages/image-io/typescript/src/index.ts
index 0e982eb32..c560afd7f 100644
--- a/packages/image-io/typescript/src/index.ts
+++ b/packages/image-io/typescript/src/index.ts
@@ -487,6 +487,9 @@ export type { WasmZstdWriteImageOptions }
 import wasmZstdWriteImage from './wasm-zstd-write-image.js'
 export { wasmZstdWriteImage }
 
+import extensionToImageIo from './extension-to-image-io.js'
+export { extensionToImageIo }
+
 export type { BinaryFile } from 'itk-wasm'
 export type { JsonCompatible } from 'itk-wasm'
 export type { Image } from 'itk-wasm'
diff --git a/packages/image-io/write-image.cxx b/packages/image-io/write-image.cxx
index 2de92abe7..8975ea130 100644
--- a/packages/image-io/write-image.cxx
+++ b/packages/image-io/write-image.cxx
@@ -117,7 +117,7 @@ int writeImage(itk::wasm::InputImageIO & inputImageIO, itk::wasm::OutputTextStre
   {
     for (unsigned int dd = 0; dd < dimension; ++dd)
     {
-      direction[dd] = directionContainer->GetElement(dim*dimension + dd);
+      direction[dd] = directionContainer->GetElement(dim + dimension*dd);
     }
     imageIO->SetDirection(dim, direction);
     imageIO->SetOrigin(dim, inputImageIOBase->GetOrigin(dim));