oleaut32: Add support for saving an empty picture.

dlls/oleaut32/olepicture.c

@@ -1757,6 +1757,12 @@ static HRESULT WINAPI OLEPictureImpl_Save(
     TRACE("%p %p %d\n", This, pStm, fClearDirty);
 
     switch (This->desc.picType) {
+    case PICTYPE_NONE:
+        header[0] = 0x0000746c;
+        header[1] = 0;
+        hResult = IStream_Write(pStm, header, 2 * sizeof(DWORD), &dummy);
+        break;
+
     case PICTYPE_ICON:
         if (This->bIsDirty || !This->data) {
             if (!serializeIcon(This->desc.u.icon.hicon, &pIconData, &iDataSize)) {

dlls/oleaut32/tests/olepicture.c

@@ -1095,11 +1095,9 @@ static void test_load_save_empty_picture(void)
     ok(hr == S_OK, "QueryInterface error %#x\n", hr);
 
     hr = IPersistStream_Save(src_stream, dst_stream, TRUE);
-todo_wine
     ok(hr == S_OK, "Save error %#x\n", hr);
 
     mem = GlobalLock(hmem);
-todo_wine
     ok(!memcmp(mem, "lt\0\0", 4), "got wrong stream header %04x\n", mem[0]);
     ok(mem[1] == 0, "expected stream size 0, got %u\n", mem[1]);
     GlobalUnlock(hmem);