diff --git a/src/server/services/wms/qgswmsrenderer.cpp b/src/server/services/wms/qgswmsrenderer.cpp
index cc0c096872b3..5b253189a1c8 100644
--- a/src/server/services/wms/qgswmsrenderer.cpp
+++ b/src/server/services/wms/qgswmsrenderer.cpp
@@ -1043,7 +1043,7 @@ namespace QgsWms
     return true;
   }
 
-  QImage *QgsRenderer::getMap()
+  std::unique_ptr<QImage> QgsRenderer::getMap()
   {
     // check size
     if ( !mContext.isValidWidthHeight() )
@@ -1078,7 +1078,7 @@ namespace QgsWms
     mapSettings.setLayers( layers );
 
     // rendering step for layers
-    QPainter *renderedPainter = layersRendering( mapSettings, *image );
+    QPainter *renderedPainter = layersRendering( mapSettings, image.get() );
     if ( !renderedPainter ) // job has been canceled
     {
       return nullptr;
@@ -1102,7 +1102,7 @@ namespace QgsWms
     {
       return nullptr;
     }
-    return image.release();
+    return image;
   }
 
   std::unique_ptr<QgsDxfExport> QgsRenderer::getDxf()
@@ -3356,7 +3356,7 @@ namespace QgsWms
     mTemporaryLayers.clear();
   }
 
-  QPainter *QgsRenderer::layersRendering( const QgsMapSettings &mapSettings, QImage &image ) const
+  QPainter *QgsRenderer::layersRendering( const QgsMapSettings &mapSettings, QImage *image ) const
   {
     QPainter *painter = nullptr;
 
@@ -3368,7 +3368,7 @@ namespace QgsWms
 #endif
     QgsMapRendererJobProxy renderJob( mContext.settings().parallelRendering(), mContext.settings().maxThreads(), &filters );
 
-    renderJob.render( mapSettings, &image, mContext.socketFeedback() );
+    renderJob.render( mapSettings, image, mContext.socketFeedback() );
     painter = renderJob.takePainter();
 
     if ( !renderJob.errors().isEmpty() )
diff --git a/src/server/services/wms/qgswmsrenderer.h b/src/server/services/wms/qgswmsrenderer.h
index 3f538431c2c1..362201364920 100644
--- a/src/server/services/wms/qgswmsrenderer.h
+++ b/src/server/services/wms/qgswmsrenderer.h
@@ -129,7 +129,7 @@ namespace QgsWms
        * takes ownership of the image object).
        * \since QGIS 3.8
        */
-      QImage *getMap();
+      std::unique_ptr<QImage> getMap();
 
       /**
        * Returns the map as DXF data
@@ -169,7 +169,7 @@ namespace QgsWms
       QList<QgsMapLayer *> highlightLayers( QList<QgsWmsParametersHighlightLayer> params );
 
       // Rendering step for layers
-      QPainter *layersRendering( const QgsMapSettings &mapSettings, QImage &image ) const;
+      QPainter *layersRendering( const QgsMapSettings &mapSettings, QImage *image ) const;
 
       // Rendering step for annotations
       void annotationsRendering( QPainter *painter, const QgsMapSettings &mapSettings ) const;