$im = imagecreate(500, 500); //Define the start and end colors for the gradient $start_color = imagecolorallocate($im, 255, 0, 0); $end_color = imagecolorallocate($im, 0, 0, 255); //Set the background gradient imagefilledrectangle($im, 0, 0, 500, 500, IMG_COLOR_GRADIENT_VERTICAL | IMG_COLOR_GRADIENT_START_COLOR($start_color) | IMG_COLOR_GRADIENT_END_COLOR($end_color)); //Output the image header('Content-Type: image/png'); imagepng($im); imagedestroy($im);In this example, we create an image with a size of 500 by 500 pixels, then we define the start and end colors for the gradient (red and blue). We then use the SetBackgroundGradient function to fill the rectangle with a vertical gradient between the start and end colors. Finally, we output the image in PNG format. It is difficult to determine which package or library this code is using without further context. It could be using the built-in PHP image functions or a third-party image manipulation library like imagick.