cut video thumbnails in php - php

Question

I have found a code that pull out a thumbnail from a video and its work!
but when I trying to make the php file to print the image with the Content-Type its return an error, when i tried to save it to the server its work fine!
the code:
<?php
function captureVideoPosterImg($movie_file = '')
{
extension_loaded('ffmpeg');
// Instantiates the class ffmpeg_movie so we can get the information you want the video
$movie = new ffmpeg_movie($movie_file);
// Get The duration of the video in seconds
echo $Duration = round($movie->getDuration(), 0);
// Get the number of frames of the video
$TotalFrames = $movie->getFrameCount();
// Get the height in pixels Video
$height = $movie->getFrameHeight();
// Get the width of the video in pixels
$width = $movie->getFrameWidth();
//Receiving the frame from the video and saving
// Need to create a GD image ffmpeg-php to work on it
$image = imagecreatetruecolor($width, $height);
// Create an instance of the frame with the class ffmpeg_frame
$Frame = new ffmpeg_frame($image);
// Choose the frame you want to save as jpeg
$thumbnailOf = (int) round($movie->getFrameCount() / 2.5);
// Receives the frame
$frame = $movie->GetFrame($thumbnailOf);
// Convert to a GD image
$image = $frame->toGDImage();
// Save to disk.
//echo $movie_file.'.jpg';
header('Content-Type: image/jpeg');
imagejpeg($image,null,100);
}
echo captureVideoPosterImg("smovie.mp4");
?>
the file in convert to UTF8 without bom.
thx!