Create image verification code with PHP

Process:
1). Create an image resource, and all subsequent operations will be based on this image resource.
$im=imagecreate(200,200)
2). In the image resource, define a color (the first call will automatically fill it as the background color).
Imagecolorallocate($im,0,102,255);
$white=imagecolorallocate($im,255,255,255);
3). In the image resource, draw graphics and enter text.
(1) Coordinate system: the upper left corner of the image resource, which is 0,0 point
(2) All the following coordinates refer to: this coordinate system, the coordinates of the upper left corner of a certain position
(2) Straight line: imageline($im, 0, 0, 200, 200, $white);
(3) Line: imageline($im, 200, 0, 0, 200, $white);
(3) Character: imagestring($im, 5, 80, 20, "Mr.Lee", $white);
4). Output the final graphics. It can be output directly or generate a file
If it is output directly, you need to use header() to tell the browser the type of image currently output
header('Content-Type: image/png');
imagepng($im);
5 ).Clear all resources
  imagedestroy($im);

The above introduces the creation of image verification code in PHP, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.