diff --git a/preview/PreviewImage.cpp b/preview/PreviewImage.cpp
index b3841962..7fa14b18 100644
--- a/preview/PreviewImage.cpp
+++ b/preview/PreviewImage.cpp
@@ -223,9 +223,9 @@ void PreviewImage::Configure(const DiffractionExperiment &in_experiment, const P
     pixel_depth_bytes = experiment.GetByteDepthImage();
     pixel_is_signed = experiment.IsPixelSigned();
 
-    mask = std::vector<uint8_t>(experiment.GetPixelsNum(), 0);
+    mask.resize(experiment.GetPixelsNum(), 0);
 
-    std::vector<uint32_t> mask_tmp = pixel_mask.GetMask(experiment);
+    auto &mask_tmp = pixel_mask.GetMask(experiment);
     for (int i = 0; i < experiment.GetPixelsNum(); i++) {
         if (((mask_tmp[i] & (1 << PixelMask::ModuleGapPixelBit)) != 0)
             || ((mask_tmp[i] & (1 << PixelMask::ChipGapPixelBit)) != 0)
@@ -235,6 +235,8 @@ void PreviewImage::Configure(const DiffractionExperiment &in_experiment, const P
             mask[i] = MaskDet;
         else if ((mask_tmp[i] & (1 << PixelMask::UserMaskedPixelBit)) != 0)
             mask[i] = MaskUsr;
+        else
+            mask[i] = 0;
     }
 }