Resizing image don't work for every image - php

Question

When I am doing resizing and converting picture to jpeg/jpg it isnt working for every PNG and JPG file, and I dont why? File isnt uploaded into server but information of path is stored into database.
This is code for resizing (also for png I am doing filling with white instead of transparency). I am using GD module not Imagick because I dont have Imagick installed on server.
function imagecreatefromfile( $filename ) {
if (!file_exists($filename)) {
throw new InvalidArgumentException('File "'.$filename.'" not found.');
}
switch ( strtolower( pathinfo( $filename, PATHINFO_EXTENSION ))) {
case 'jpeg':
case 'jpg':
return imagecreatefromjpeg($filename);
break;
case 'png':
return imagecreatefrompng($filename);
break;
default:
throw new InvalidArgumentException('File "'.$filename.'" is not valid jpg or png.');
break;
}
}
/* do resizing of picture */
$src = imagecreatefromfile($target);
$path1 = strtolower( pathinfo( $target, PATHINFO_EXTENSION ));
list ($width, $height) = getimagesize($target);
$newwidth = 300;
if($heigth > $width){
$newheight = ($height/$width)*$newwidth;
}
else if($width == $height){
$newheight = 300;
}
else if($width > $height){
$newheight = ($width/$height)*$newwidth;
}
unlink($target);
switch ($path1)
{
case 'jpg':
$tmp = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($tmp, $src, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
imagejpeg($tmp, $target, 90);
imagedestroy($src);
imagedestroy($tmp);
break;
case 'png':
$backgroundImg = imagecreatetruecolor($width, $height);
$color = imagecolorallocate($backgroundImg, 255, 255, 255);
imagefill($backgroundImg, 0, 0, $color);
imagecopy($backgroundImg, $src, 0, 0, 0, 0, $width, $height);
$tmp2 = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($tmp2, $backgroundImg, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
imagejpeg($tmp2, $target, 90);
imagedestroy($src);
imagedestroy($backgroundImg);
imagedestroy($tmp2);
break;
}
?>