can't resize an image using php - php

Question

I have a php code to get an image and resize it. Can't get the output as expected.. Please help me figure out what the exact problem is..!!
<?php
$picture_source = 'image.png';
if ($picture_source != null){
$img1=file_get_contents($picture_source);
$new_img1 = resizeImage($img1, 200, 200);
file_put_contents("i1.png", $new_img1);
}
function resizeImage($img,$newwidth,$newheight) {
list($width, $height) = getimagesizefromstring($img);
$thumb = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($thumb, $img, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
return $thumb;
}

Answer 1

You've got some confusion with your variable names and types. You're trying to deal with a filename, the file contents, and an image resource at the same time, and you're using the wrong ones for a few of the functions.
imagecopyresampled takes two image resources (source and destination), but you're passing it the file contents in place of the source.
file_put_contents takes a string for the file contents, but you're passing it the resized image resource.
PHP has native functions for reading the image dimensions and creating an image resource from a filename, so you shouldn't need to ever have the source file contents available as a string.
If you change a few of the variable names and function calls around, you end up with:
<?php
$sourceFilename = 'image.png';
if ($sourceFilename != null){
$newImg = resizeImage($sourceFilename, 200, 200);
imagepng($newImg, "i1.png");
}
function resizeImage($imgFilename, $newWidth, $newHeight) {
list($width, $height) = getimagesize($imgFilename);
$img = imagecreatefrompng($imgFilename);
$thumb = imagecreatetruecolor($newWidth, $newHeight);
imagecopyresampled($thumb, $img, 0, 0, 0, 0, $newWidth, $newHeight, $width, $height);
return $thumb;
}
Also, you should turn on PHP notices and warnings in your development environment - they will have been trying to help you.