diff --git a/dlls/windowscodecs/bmpdecode.c b/dlls/windowscodecs/bmpdecode.c
index afe48814e26..e2378bacea2 100644
--- a/dlls/windowscodecs/bmpdecode.c
+++ b/dlls/windowscodecs/bmpdecode.c
@@ -66,7 +66,7 @@ typedef struct {
     BITMAPV5HEADER bih;
 } BmpFrameDecode;
 
-HRESULT WINAPI BmpFrameDecode_QueryInterface(IWICBitmapFrameDecode *iface, REFIID iid,
+static HRESULT WINAPI BmpFrameDecode_QueryInterface(IWICBitmapFrameDecode *iface, REFIID iid,
     void **ppv)
 {
     BmpFrameDecode *This = (BmpFrameDecode*)iface;
@@ -274,7 +274,7 @@ static HRESULT BmpDecoder_ReadHeaders(BmpDecoder* This, IStream *stream)
     return S_OK;
 }
 
-HRESULT WINAPI BmpDecoder_QueryInterface(IWICBitmapDecoder *iface, REFIID iid,
+static HRESULT WINAPI BmpDecoder_QueryInterface(IWICBitmapDecoder *iface, REFIID iid,
     void **ppv)
 {
     BmpDecoder *This = (BmpDecoder*)iface;
diff --git a/dlls/windowscodecs/imgfactory.c b/dlls/windowscodecs/imgfactory.c
index f422a8a5b5a..58566618645 100644
--- a/dlls/windowscodecs/imgfactory.c
+++ b/dlls/windowscodecs/imgfactory.c
@@ -39,7 +39,7 @@ typedef struct {
     LONG ref;
 } ImagingFactory;
 
-HRESULT WINAPI ImagingFactory_QueryInterface(IWICImagingFactory *iface, REFIID iid,
+static HRESULT WINAPI ImagingFactory_QueryInterface(IWICImagingFactory *iface, REFIID iid,
     void **ppv)
 {
     ImagingFactory *This = (ImagingFactory*)iface;