Código PHP:
<?php
function makeThumbnail($file, $t_ht = 100) {
$image_info = getImageSize($file) ; // see EXIF for faster way
switch ($image_info['mime']) {
case 'image/gif':
if (imagetypes() & IMG_GIF) { // not the same as IMAGETYPE
$o_im = imageCreateFromGIF($file) ;
} else {
$ermsg = 'GIF images are not supported<br />';
}
break;
case 'image/jpeg':
if (imagetypes() & IMG_JPG) {
$o_im = imageCreateFromJPEG($file) ;
} else {
$ermsg = 'JPEG images are not supported<br />';
}
break;
case 'image/png':
if (imagetypes() & IMG_PNG) {
$o_im = imageCreateFromPNG($file) ;
} else {
$ermsg = 'PNG images are not supported<br />';
}
break;
case 'image/wbmp':
if (imagetypes() & IMG_WBMP) {
$o_im = imageCreateFromWBMP($file) ;
} else {
$ermsg = 'WBMP images are not supported<br />';
}
break;
default:
$ermsg = $image_info['mime'].' images are not supported<br />';
break;
}
if (!isset($ermsg)) {
$o_wd = imagesx($o_im) ;
$o_ht = imagesy($o_im) ;
// thumbnail width = target * original width / original height
$t_wd = round($o_wd * $t_ht / $o_ht) ;
$t_im = imageCreateTrueColor($t_wd,$t_ht);
imageCopyResampled($t_im, $o_im, 0, 0, 0, 0, $t_wd, $t_ht, $o_wd, $o_ht);
imageJPEG($t_im);
imageDestroy($o_im);
imageDestroy($t_im);
}
return isset($ermsg)?$ermsg:NULL;
}
header("Content-type: image/jpeg");
makeThumbnail($_GET['imagename'], 150);
?>
Saludos