Mejor te lo pongo en codigo:
Código :
<?php
function photoCreateCropThumb ($p_thumb_file, $p_photo_file, $p_max_size, $p_quality = 75) {
$pic = @imagecreatefromjpeg($p_photo_file);
if ($pic) {
$thumb = @imagecreatetruecolor ($p_max_size, $p_max_size) or die ("Can't create Image!");
$width = imagesx($pic);
$height = imagesy($pic);
if ($width < $height) {
$twidth = $p_max_size;
$theight = $twidth * $height / $width;
imagecopyresized($thumb, $pic, 0, 0, 0, ($height/2)-($width/2), $twidth, $theight, $width, $height);
} else {
$theight = $p_max_size;
$twidth = $theight * $width / $height;
imagecopyresized($thumb, $pic, 0, 0, ($width/2)-($height/2), 0, $twidth, $theight, $width, $height);
}
ImageJPEG ($thumb, $p_thumb_file, $p_quality);
}
}
?>