tag width or height; here we are creating a new image header("Content-type:image/jpeg"); $image = imagecreatefromjpeg("img/girl_lookaway.jpg"); $width = imagesx($image); $height = imagesy($image); $ratio = $width/$height; $new_width = 300; $new_height = $new_width / $ratio; $image_resized = imagecreatetruecolor($new_width, $new_height); imagecopyresampled($image_resized, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height); imagejpeg($image_resized); ?>