Uploaded image: converting format - php

Question

I want to convert a uploaded image to its original format, (jpg, jpeg rpng, etc.) but I need to re-size these images to be 150px width and 210px height. Is it possible to change the size while copying, or do I have to convert it?
This was unsucessful:
$uploaddir1 = "/home/myweb/public_html/temp/sfds454.png";
$uploaddir2 = "/home/myweb/public_html/images/sfds454.png";
$cmd = "/usr/bin/ffmpeg -i $uploaddir1 -vframes 1 -s 150x210 -r 1 -f mjpeg $uploaddir2";
#exec($cmd);

Answer 1

You can use gd instead of ffmpeg. To convert or resize an image, see this example: http://ryanfait.com/resources/php-image-resize/resize.txt
Php lib for gd:
http://php.net/manual/en/function.imagecopyresampled.php
There is also some samples of resizing scripts in that page.

Answer 2

I recently had to solve just this problem, and implemented this simple caching solution:
<?php
function send($name, $ext) {
$fp = fopen($name, 'rb');
// send the right headers
header("Content-Type: image/$ext");
header("Content-Length: " . filesize($name));
// dump the picture and stop the script
fpassthru($fp);
exit;
}
error_reporting(E_ALL);
ini_set('display_errors', 'On');
if (isset($_REQUEST['fp'])) {
$ext = pathinfo($_REQUEST['fp'], PATHINFO_EXTENSION);
$allowedExt = array('png', 'jpg', 'jpeg');
if (!in_array($ext, $allowedExt)) {
echo 'fail';
}
if (!isset($_REQUEST['w']) && !isset($_REQUEST['h'])) {
send($_REQUEST['fp']);
}
else {
$w = $_REQUEST['w'];
$h = $_REQUEST['h'];
//use height, width, modification time and path to generate a hash
//that will become the file name
$filePath = realpath($_REQUEST['fp']);
$cachePath = md5($filePath.filemtime($filePath).$h.$w);
if (!file_exists("tmp/$cachePath")) {
exec("gm convert -quality 80% -colorspace RGB -resize " .$w .'x' . $h . " $filePath tmp/$cachePath");
}
send("tmp/$cachePath", $ext);
}
}
?>
Some things that I noticed:
Graphicsmagick converted much faster than imagemagick, although I did not test conversion with cuda processing.
For the final product I re-implemented this code in ASP using the language's native graphics library. This was much faster again but would break if out-of-memory errors occurred (worked fine on my workstation, but wouldn't work on 4GB RAM server).