Uploading Jpeg fails with this function - php

Question

So this function works almost perfectly but it fails with jpeg, works fine with jpg I think because the file extension bit i am not sure.
Anyone can see where I have gone wrong? I am also thinking to get the file extension by reading backward to the dot to be sure the file does not have other dots. Some ideas about that would be welcome.
function watermark($OriginalFileUpload,$DestinationWaterMarkedFile)
{
$OutPutFile = $DestinationWaterMarkedFile;
$imagesource = $OriginalFileUpload;
$File_Extention = explode(".", $imagesource); // this will fail if some file has two dots
$File_Extention = end($File_Extention);
$File_Extention = strtolower($File_Extention);
if($File_Extention == ".gif") $New_Image = #imagecreatefromgif($imagesource);
if($File_Extention == ".jpg") $New_Image = #imagecreatefromjpeg($imagesource);
if($File_Extention == ".png") $New_Image = #imagecreatefrompng($imagesource);
if($File_Extention == ".jpeg") $New_Image = #imagecreatefromjpeg($imagesource);
$watermark = imagecreatefrompng('Logo.png');
$wm_x = imagesx($watermark);
$wm_y = imagesy($watermark);
$img_x = imagesx($New_Image);
$img_y = imagesy($New_Image);
$wm_scale = 6; // 2 = 1/2
$wm_w = $img_x/$wm_scale;
$wm_aspect = $wm_y/$wm_x;
$wm_h = (int) ($wm_aspect * $wm_w);
$margin_scale = 6; // 2 = 1/2
$margen_right = $wm_w/$margin_scale;
$margen_bottom = $wm_h/$margin_scale;
$dst_x = $img_x - $wm_w - $margen_right;
$dst_y = $img_y - $wm_h - $margen_bottom;
imagecopyresized ($New_Image, $watermark, $dst_x, $dst_y, 0, 0, $wm_w, $wm_h, $wm_x, $wm_y);
imagejpeg($New_Image,$OutPutFile,100,NULL); // writes the watermarked file to the Marked folder
imagedestroy($New_Image);
}