How to show image that was edited with PHP - php

Question

I have an image which can show polylines. I can show the image perfectly but when i apply into website which not using header("Content-type: image/png"); i got problem.
Can i show the image that has been edited with PHP in website not just image.
here's my code
<?php
$img = imagecreatefromjpeg('1967_NL_MAJENEresize.jpg'); //you can change image name
$white = imagecolorallocate($img, 255, 255, 255);
$red = imagecolorallocate($img, 255, 0, 0);
imagesetthickness($img, 4);
imagefill($img, 0, 0, $white);
imageline($img, 100, 80, 210, 380, $white); //x1, y1, x2, y2
imageline($img, 200, 80, 210, 380, $white);
imageline($img, 200, 80, 310, 580, $white);
imagefilledrectangle ($img, (100-5), (80-5), 100+10, 80+10, $red);
imagefilledrectangle ($img, (210-5), (380-5), 210+10, 380+10, $red);
imagefilledrectangle ($img, (200-5), (80-5), 200+10, 80+10, $red);
imagefilledrectangle ($img, (310-5), (580-5), 310+10, 580+10, $red);
header("Content-type: image/png");
imagepng($img);
imagedestroy($img);
?>

Answer 1

You shouldn't include the image generating code in existing content, instead have a dedicated script to create the image using the correct header.
Link to the image from your content by using <img> tag
generate-image.php:
<?php
$imagefile = preg_replace('/[^A-Za-z0-9_\-]/', '_', $_GET['filename']);
$img = imagecreatefromjpeg($imgfile); //you can change image name
$white = imagecolorallocate($img, 255, 255, 255);
$red = imagecolorallocate($img, 255, 0, 0);
imagesetthickness($img, 4);
imagefill($img, 0, 0, $white);
imageline($img, 100, 80, 210, 380, $white); //x1, y1, x2, y2
imageline($img, 200, 80, 210, 380, $white);
imageline($img, 200, 80, 310, 580, $white);
imagefilledrectangle ($img, (100-5), (80-5), 100+10, 80+10, $red);
imagefilledrectangle ($img, (210-5), (380-5), 210+10, 380+10, $red);
imagefilledrectangle ($img, (200-5), (80-5), 200+10, 80+10, $red);
imagefilledrectangle ($img, (310-5), (580-5), 310+10, 580+10, $red);
header("Content-type: image/png");
imagepng($img);
imagedestroy($img);
?>
index.php:
Blah Blah
<img src='generate-image.php?filename=<?= $db->row['thumbnail']; ?>'>;
blah blah