PHP image resize not working

Question

I'm trying to create a thumbnail from a JPG image, but I can't get the resized image to output properly ("contains errors").

Here's my code, I can't figure out what's wrong:

<?php   
header('Content-Type: image/jpeg');

$photos = glob($_GET['a'] . '/*.*');
$img = imagecreatefromjpeg($photos[array_rand($photos)]);

list($width, $height) = getimagesize($img);
if($width > $height) {
    $newWidth = 250;
    $newHeight = 250*$height/$width;
}
else {
    $newHeight = 250;
    $newWidth = 250*$width/$height;
}

$tmp = imagecreatetruecolor($newWidth, $newHeight);
imagecopyresampled($tmp, $img, 0, 0, 0, 0, $newWidth, $newHeight, $width, $height);

// Output the image
imagejpeg($tmp);
?>

possibly you have to install gd extension, apt-get install php7.0-gd — WayFarer, Feb 15 '18 at 15:54

score 1 · Accepted Answer · answered Feb 15 '18 at 15:56

1

The function getimagesize() requires a filename, not an image resource. It emits a warning, that's why the image was not valid, because there is a string before the image binary.

$photos = glob($_GET['a'] . '/*.*');
$filename = $photos[array_rand($photos)] ;
$img = imagecreatefromjpeg($filename);
list($width, $height) = getimagesize($filename);

or use imagesx() and imagesy() to get image size using $img.

$photos = glob($_GET['a'] . '/*.*');
$img = imagecreatefromjpeg($photos[array_rand($photos)]);
$width = imagesx($img);
$height = imagesy($img);

answered Feb 15 '18 at 15:56

Syscall

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Thanks, this was the problem! – bur Feb 15 '18 at 16:01
@bur Don't forget to remove/comment temporarily the `header()`, the next time, to see the errors, before the binary content :) – Syscall Feb 15 '18 at 16:03
Yeah, I will remember next time, should have been my first response ^^ Thanks! – bur Feb 15 '18 at 16:09

PHP image resize not working

1 Answers1