diff --git a/applets/notifications/plugin/thumbnailer.cpp b/applets/notifications/plugin/thumbnailer.cpp
--- a/applets/notifications/plugin/thumbnailer.cpp
+++ b/applets/notifications/plugin/thumbnailer.cpp
@@ -214,6 +214,7 @@
 
     auto maxSize = qMax(m_size.width(), m_size.height());
     KIO::PreviewJob *job = KIO::filePreview(KFileItemList({KFileItem(m_url)}), QSize(maxSize,maxSize));
+    job->setScaleType(KIO::PreviewJob::Scaled);
     job->setIgnoreMaximumSize(true);
 
     connect(job, &KIO::PreviewJob::gotPreview, this, [this](const KFileItem &item, const QPixmap &preview) {