diff --git a/dlls/windowscodecs/converter.c b/dlls/windowscodecs/converter.c
index 86cdf55c75c..a83f4a52d7a 100644
--- a/dlls/windowscodecs/converter.c
+++ b/dlls/windowscodecs/converter.c
@@ -850,11 +850,27 @@ static HRESULT WINAPI FormatConverter_CopyPixels(IWICFormatConverter *iface,
     const WICRect *prc, UINT cbStride, UINT cbBufferSize, BYTE *pbBuffer)
 {
     FormatConverter *This = (FormatConverter*)iface;
+    WICRect rc;
+    HRESULT hr;
     TRACE("(%p,%p,%u,%u,%p)\n", iface, prc, cbStride, cbBufferSize, pbBuffer);
 
     if (This->source)
+    {
+        if (!prc)
+        {
+            UINT width, height;
+            hr = IWICBitmapSource_GetSize(This->source, &width, &height);
+            if (FAILED(hr)) return hr;
+            rc.X = 0;
+            rc.Y = 0;
+            rc.Width = width;
+            rc.Height = height;
+            prc = &rc;
+        }
+
         return This->dst_format->copy_function(This, prc, cbStride, cbBufferSize,
             pbBuffer, This->src_format->format);
+    }
     else
         return WINCODEC_ERR_NOTINITIALIZED;
 }
diff --git a/dlls/windowscodecs/fliprotate.c b/dlls/windowscodecs/fliprotate.c
index 7dac252b03c..dbbb95733f0 100644
--- a/dlls/windowscodecs/fliprotate.c
+++ b/dlls/windowscodecs/fliprotate.c
@@ -140,6 +140,7 @@ static HRESULT WINAPI FlipRotator_CopyPixels(IWICBitmapFlipRotator *iface,
     UINT y;
     UINT srcy, srcwidth, srcheight;
     WICRect rc;
+    WICRect rect;
 
     TRACE("(%p,%p,%u,%u,%p)\n", iface, prc, cbStride, cbBufferSize, pbBuffer);
 
@@ -155,6 +156,18 @@ static HRESULT WINAPI FlipRotator_CopyPixels(IWICBitmapFlipRotator *iface,
     hr = IWICBitmapSource_GetSize(This->source, &srcwidth, &srcheight);
     if (FAILED(hr)) return hr;
 
+    if (!prc)
+    {
+        UINT width, height;
+        hr = IWICBitmapSource_GetSize(iface, &width, &height);
+        if (FAILED(hr)) return hr;
+        rect.X = 0;
+        rect.Y = 0;
+        rect.Width = width;
+        rect.Height = height;
+        prc = ▭
+    }
+
     for (y=prc->Y; y - prc->Y < prc->Height; y++)
     {
         if (This->flip_y)
diff --git a/dlls/windowscodecs/gifformat.c b/dlls/windowscodecs/gifformat.c
index 239d25d841b..5cbdc261caa 100644
--- a/dlls/windowscodecs/gifformat.c
+++ b/dlls/windowscodecs/gifformat.c
@@ -184,9 +184,21 @@ static HRESULT copy_interlaced_pixels(const BYTE *srcbuffer,
     const BYTE *src;
     BYTE *dst;
     UINT y;
+    WICRect rect;
 
-    if (rc->X < 0 || rc->Y < 0 || rc->X+rc->Width > srcwidth || rc->Y+rc->Height > srcheight)
-        return E_INVALIDARG;
+    if (!rc)
+    {
+        rect.X = 0;
+        rect.Y = 0;
+        rect.Width = srcwidth;
+        rect.Height = srcheight;
+        rc = &rect;
+    }
+    else
+    {
+        if (rc->X < 0 || rc->Y < 0 || rc->X+rc->Width > srcwidth || rc->Y+rc->Height > srcheight)
+            return E_INVALIDARG;
+    }
 
     if (dststride < rc->Width)
         return E_INVALIDARG;
diff --git a/dlls/windowscodecs/jpegformat.c b/dlls/windowscodecs/jpegformat.c
index 5243d948c9b..c3cd4558d89 100644
--- a/dlls/windowscodecs/jpegformat.c
+++ b/dlls/windowscodecs/jpegformat.c
@@ -519,8 +519,24 @@ static HRESULT WINAPI JpegDecoder_Frame_CopyPixels(IWICBitmapFrameDecode *iface,
     UINT data_size;
     UINT max_row_needed;
     jmp_buf jmpbuf;
+    WICRect rect;
     TRACE("(%p,%p,%u,%u,%p)\n", iface, prc, cbStride, cbBufferSize, pbBuffer);
 
+    if (!prc)
+    {
+        rect.X = 0;
+        rect.Y = 0;
+        rect.Width = This->cinfo.output_width;
+        rect.Height = This->cinfo.output_height;
+        prc = &rect;
+    }
+    else
+    {
+        if (prc->X < 0 || prc->Y < 0 || prc->X+prc->Width > This->cinfo.output_width ||
+            prc->Y+prc->Height > This->cinfo.output_height)
+            return E_INVALIDARG;
+    }
+
     if (This->cinfo.out_color_space == JCS_GRAYSCALE) bpp = 8;
     else if (This->cinfo.out_color_space == JCS_CMYK) bpp = 32;
     else bpp = 24;
diff --git a/dlls/windowscodecs/main.c b/dlls/windowscodecs/main.c
index ff543d5000f..906ea16541e 100644
--- a/dlls/windowscodecs/main.c
+++ b/dlls/windowscodecs/main.c
@@ -53,9 +53,21 @@ HRESULT copy_pixels(UINT bpp, const BYTE *srcbuffer,
 {
     UINT bytesperrow;
     UINT row_offset; /* number of bits into the source rows where the data starts */
+    WICRect rect;
 
-    if (rc->X < 0 || rc->Y < 0 || rc->X+rc->Width > srcwidth || rc->Y+rc->Height > srcheight)
-        return E_INVALIDARG;
+    if (!rc)
+    {
+        rect.X = 0;
+        rect.Y = 0;
+        rect.Width = srcwidth;
+        rect.Height = srcheight;
+        rc = &rect;
+    }
+    else
+    {
+        if (rc->X < 0 || rc->Y < 0 || rc->X+rc->Width > srcwidth || rc->Y+rc->Height > srcheight)
+            return E_INVALIDARG;
+    }
 
     bytesperrow = ((bpp * rc->Width)+7)/8;
 
diff --git a/dlls/windowscodecs/tiffformat.c b/dlls/windowscodecs/tiffformat.c
index 645cfb05a52..12561106468 100644
--- a/dlls/windowscodecs/tiffformat.c
+++ b/dlls/windowscodecs/tiffformat.c
@@ -799,12 +799,24 @@ static HRESULT WINAPI TiffFrameDecode_CopyPixels(IWICBitmapFrameDecode *iface,
     HRESULT hr=S_OK;
     BYTE *dst_tilepos;
     UINT bytesperrow;
+    WICRect rect;
 
     TRACE("(%p,%p,%u,%u,%p)\n", iface, prc, cbStride, cbBufferSize, pbBuffer);
 
-    if (prc->X < 0 || prc->Y < 0 || prc->X+prc->Width > This->decode_info.width ||
-        prc->Y+prc->Height > This->decode_info.height)
-        return E_INVALIDARG;
+    if (!prc)
+    {
+        rect.X = 0;
+        rect.Y = 0;
+        rect.Width = This->decode_info.width;
+        rect.Height = This->decode_info.height;
+        prc = &rect;
+    }
+    else
+    {
+        if (prc->X < 0 || prc->Y < 0 || prc->X+prc->Width > This->decode_info.width ||
+            prc->Y+prc->Height > This->decode_info.height)
+            return E_INVALIDARG;
+    }
 
     bytesperrow = ((This->decode_info.bpp * prc->Width)+7)/8;