Solution 1:

You could attach the image (as a pixmap) to a label then add that to your layout...

...

QPixmap image("blah.jpg");

QLabel *imageLabel = new QLabel();
imageLabel->setPixmap(image);

mainLayout.addWidget(imageLabel);

...

Apologies, this is using Jambi (Qt for Java) so the syntax is different, but the theory is the same.

Solution 2:

#include ...

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QGraphicsScene scene;
    QGraphicsView view(&scene);
    QGraphicsPixmapItem item(QPixmap("c:\\test.png"));
    scene.addItem(&item);
    view.show();
    return a.exec();
}

This should work. :) List of supported formats can be found here

Solution 3:

If the only thing you want to do is drop in an image onto a widget withouth the complexity of the graphics API, you can also just create a new QWidget and set the background with StyleSheets. Something like this:

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
{
    ...
    QWidget *pic = new QWidget(this);
    pic->setStyleSheet("background-image: url(test.png)");
    pic->setGeometry(QRect(50,50,128,128));
    ...
}

Solution 4:

I want to display .jpg image in an Qt UI

The simpliest way is to use QLabel for this:

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);
    QLabel label("<img src='image.jpg' />");
    label.show();
    return a.exec();
}