To view this content, you need to install Java from java.com

move your mouse pointer from left to right above the applet to change 'curFace'
notice how the copy of the mouth doesn't change..

Source code: img_copy_test

Built with Processing

To view this content, you need to install Java from java.com

with updatePixels() called after the copy() the copied image is updated correctly..

Source code: img_copy_test_solution

Built with Processing