QByteArray

bool QPixmap::save(QIODevice *device, const char *format = Q_NULLPTR, int quality = -1) const

This is an overloaded function.

This function writes a QPixmap to the given device using the specified image file format and quality factor. This can be used, for example, to save a pixmap directly into a QByteArray:

          QPixmap pixmap;

          QByteArray bytes;

          QBuffer buffer(&bytes);

          buffer.open(QIODevice::WriteOnly);

          pixmap.save(&buffer, "PNG"); // writes pixmap into bytes in PNG format