Java add image from an event

Do not invoke repaint inside paintComponent Invoke super.paintComponent and then draw the image

Also, depending on the layout manager, this component will have a preferred size of (0, 0), and therefore will not be visible.

For more information, see 2D Graphics.

Edit - Note that dynamically adding a component will force you to revalidate the container and issue a repaint request so the layout manager will layout its components again and remove any visual artifacts. Also, for more information regarding images, see Working with Images.

Anyway, the simplest approach would probably be to set the image as the icon of a JLabel instance and add that to the container. There's really no need to reinvent the wheel here.

Answers

g.drawImage(monkey, 20, 100, this);

..would most likely have fixed the problem in the original code. It was a combined problem of:

Loading the image in an asynchronous way. (Toolkit.getImage() as opposed to ImageIO.read().) Painting it to a 'blinkered' ImageObserver. The JComponent implements ImageObserver. As soon as the image is totally loaded (as well as a few points before that), the observer will be informed, triggering a repaint().