not display gif/jpeg

hi all
I have a problem with "Blobbing data with PHP and MySQL" by Mitchell Harper, a very(!) simple problem but every other message on this forum or on others forums haven't solved yet.
The script works well for .txt files, but not for gif or jpeg files. If I don't specify "Content-type: image/gif(or jpeg)" it sends me (as I expected) the binary code of the file, but with the proper Content-type, it displays "The image 'downloadfile.php ' cannot be displayed, because it contains errors".
Naturally I tried with different jpegs or gifs.
If it can be useful, output of "grabfile.php" is:
"The details of the uploaded file are shown below:

File name: picture.jpg
File type: image/jpeg
File size: 15590
Uploaded to: C:\WINNT\TEMP\php6.tmp"
So (I think) the upload operation works fine.

I'using PHP4.0.6 and MySQL3.23.43 on Windows2000.
Any help will be appreciated.
Thanks in advance

Would it be possible to post or attach the code you're using to store the file as well as pull it back for display?