images2张图片合并

<?php 
  $path_1 = "./sucai/big.png";
  $path_2 = "./sucai/small.jpg";
  $image_1 = imagecreatefrompng($path_1);
  $image_2 = imagecreatefromjpeg($path_2);
  $image_3 = imageCreatetruecolor(imagesx($image_1),imagesy($image_1));
  $color = imagecolorallocate($image_3, 255, 255, 255);
  imagefill($image_3, 0, 0, $color);
  imageColorTransparent($image_3, $color);
    imagecopyresampled($image_3,$image_1,0,0,0,0,imagesx($image_1),imagesy($image_1),imagesx($image_1),imagesy($image_1));
  imagecopymerge($image_3,$image_2, 230,43,0,0,imagesx($image_2),imagesy($image_2), 100);
  //将画布保存到指定的gif文件
  imagegif($image_3, "all.jpg");
  echo "<img src='all.jpg'>";