如何在PHP中绘制png图像？

$image = imagecreatetruecolor(538,616);

$black = imagecolorallocate($image,0,0,0);

imagefill($image,0,0,$black);

I have already draw a black image i want draw a file suppose 3.png on it .. How to do that ?

You have to load an image you want to draw and then use imagecopy() to draw it:

// the part you already have; creates 538x616 px black image
$image = imagecreatetruecolor(538,616);
$black = imagecolorallocate($image,0,0,0);
imagefill($image,0,0,$black);

// load image from file and draw it onto black image;
// for loading PNG, use imagecreatefrompng()
$overlayImage = imagecreatefromjpeg('macro_photo_1.jpg');
imagecopy($image, $overlayImage, 10, 10, 0, 0, imagesx($overlayImage), imagesy($overlayImage));

// send image to the browser    
header("Content-Type: image/png");
imagepng($image);
exit;

I would also advise to go through the list of GD and Image functions to see what (and how) can be done with images in PHP.

imagepng($image);

And if you haven't already you need:

header('Content-Type: image/png');

Before you call imagepng to let the browser know it's looking at an image not an HTML page.

Saroj, http://www.php.net/manual/en/function.imagecreate.php and from same page, here is the example snippet

<?php
header("Content-Type: image/png");
$im = @imagecreate(110, 20)
or die("Cannot Initialize new GD image stream");
$background_color = imagecolorallocate($im, 0, 0, 0);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5,  "A Simple Text String", $text_color);
imagepng($im);
imagedestroy($im);
?>

HTH!