diff --git a/src/calibre/gui2/pictureflow/pictureflow.cpp b/src/calibre/gui2/pictureflow/pictureflow.cpp
index b82747841c..4e9d8a402d 100644
--- a/src/calibre/gui2/pictureflow/pictureflow.cpp
+++ b/src/calibre/gui2/pictureflow/pictureflow.cpp
@@ -1409,8 +1409,8 @@ void PictureFlow::dataChanged() { d->dataChanged(); }
 void PictureFlow::emitcurrentChanged(int index) { emit currentChanged(index); }
 
 int FlowImages::count() { return 0; }
-QImage FlowImages::image(int index) { index=0; return QImage(); }
-QString FlowImages::caption(int index) {index=0; return QString(); }
-QString FlowImages::subtitle(int index) {index=0; return QString(); }
+QImage FlowImages::image(int index) { Q_UNUSED(index); return QImage(); }
+QString FlowImages::caption(int index) { Q_UNUSED(index); return QString(); }
+QString FlowImages::subtitle(int index) { Q_UNUSED(index); return QString(); }
 
 // }}}