Resize image in PHP

Question

I\'m wanting to write some PHP code which automatically resizes any image uploaded via a form to 147x147px, but I have no idea how to go about it (I\'m a relative PHP novice

Answer 1

If you dont care about the aspect ration (i.e you want to force the image to a particular dimension), here is a simplified answer

// for jpg 
function resize_imagejpg($file, $w, $h) {
   list($width, $height) = getimagesize($file);
   $src = imagecreatefromjpeg($file);
   $dst = imagecreatetruecolor($w, $h);
   imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
   return $dst;
}

 // for png
function resize_imagepng($file, $w, $h) {
   list($width, $height) = getimagesize($file);
   $src = imagecreatefrompng($file);
   $dst = imagecreatetruecolor($w, $h);
   imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
   return $dst;
}

// for gif
function resize_imagegif($file, $w, $h) {
   list($width, $height) = getimagesize($file);
   $src = imagecreatefromgif($file);
   $dst = imagecreatetruecolor($w, $h);
   imagecopyresampled($dst, $src, 0, 0, 0, 0, $w, $h, $width, $height);
   return $dst;
}

Now let's handle the upload part. First step, upload the file to your desired directory. Then called one of the above functions based on file type (jpg, png or gif) and pass the absolute path of your uploaded file as below:

 // jpg  change the dimension 750, 450 to your desired values
 $img = resize_imagejpg('path/image.jpg', 750, 450);

The return value $img is a resource object. We can save to a new location or override the original as below:

 // again for jpg
 imagejpeg($img, 'path/newimage.jpg');

Hope this helps someone. Check these links for more on resizing Imagick::resizeImage and imagejpeg()