The following code snippet causes a deadlock of the thread pool if the number of files selected exceeds the number of available threads. The call of QImage::scaled does not return. The execution stops when calling QSemaphore::acquire in static inline void multithread_pixels_function (qimagescale_sse4.cpp).

With Qt version 5.14.0 the code works fine.

...
QStringList fileNames = QFileDialog::getOpenFileNames(nullptr, tr("Select Image Files"),
QString(),
tr("JPG (*.jpg)"));
for ( const QString& path : fileNames ) {
QtConcurrent::run([path]() {
QImage img(path);

if ( !img.isNull() )

{ img = img.scaled(100, 100, Qt::KeepAspectRatio, Qt::SmoothTransformation); }

});
}
...