diff --git a/src/ExportManager.cpp b/src/ExportManager.cpp
--- a/src/ExportManager.cpp
+++ b/src/ExportManager.cpp
@@ -473,7 +473,7 @@
 
     // construct the supported mimetype list
     const auto mimeTypes = QImageWriter::supportedMimeTypes();
-    for (auto mimeType : mimeTypes) {
+    for (const auto &mimeType : mimeTypes) {
         supportedFilters.append(QString::fromUtf8(mimeType).trimmed());
     }
 
diff --git a/src/Gui/SettingsDialog/SaveOptionsPage.cpp b/src/Gui/SettingsDialog/SaveOptionsPage.cpp
--- a/src/Gui/SettingsDialog/SaveOptionsPage.cpp
+++ b/src/Gui/SettingsDialog/SaveOptionsPage.cpp
@@ -97,7 +97,7 @@
     connect(mSaveNameFormat, &QLineEdit::textEdited, this, [&](const QString &newText) {
         QString fmt;
         const auto imageFormats = QImageWriter::supportedImageFormats();
-        for (auto item : imageFormats) {
+        for (const auto &item : imageFormats) {
             fmt = QString::fromLocal8Bit(item);
             if (newText.endsWith(QLatin1Char('.') + fmt, Qt::CaseInsensitive)) {
                 QString txtCopy = newText;
@@ -115,7 +115,7 @@
     mSaveImageFormat->addItems([&](){
         QStringList items;
         const auto formats = QImageWriter::supportedImageFormats();
-        for (auto fmt : formats) {
+        for (const auto &fmt : formats) {
             items.append(QString::fromLocal8Bit(fmt).toUpper());
         }
         return items;
diff --git a/src/QuickEditor/QuickEditor.cpp b/src/QuickEditor/QuickEditor.cpp
--- a/src/QuickEditor/QuickEditor.cpp
+++ b/src/QuickEditor/QuickEditor.cpp
@@ -108,7 +108,7 @@
         };
         for (auto& pair : mBottomHelpText) {
             prepare(pair.first);
-            for (auto item : pair.second) {
+            for (auto &item : pair.second) {
                 prepare(item);
             }
         }