question: public static BufferedImage generateRandomImage ( int numOfPixels ) throws OpenStegoException { final double ASPECT_RATIO = 4.0 / 3.0 ; int width = 0 ; int height = 0 ; byte [ ] rgbValue = new byte [ 3 ] ; BufferedImage image = null ; SecureRandom random = null ; try { random = SecureRandom . getInstance ( "SHA1PRNG" ) ; width = ( int ) Math . ceil ( Math . sqrt ( numOfPixels * ASPECT_RATIO ) ) ; height = ( int ) Math . ceil ( numOfPixels / ( double ) width ) ; image = new BufferedImage ( width , height , BufferedImage . TYPE_INT_RGB ) ; for ( int x = 0 ; x < width ; x ++ ) { for ( int y = 0 ; y < height ; y ++ ) { random . nextBytes ( rgbValue ) ; image . setRGB ( x , y , CommonUtil . byteToInt ( rgbValue [ 0 ] ) + ( CommonUtil . byteToInt ( rgbValue [ 1 ] ) << 8 ) + ( CommonUtil . byteToInt ( rgbValue [ 2 ] ) << 16 ) ) ; } } return image ; } catch ( NoSuchAlgorithmException nsaEx ) { throw new OpenStegoException ( nsaEx ) ; } }
target:  Method to generate a random image filled with noise.