(PHP 3 >= 3.0.16, PHP 4, PHP 5)
imagejpeg -- Output image to browser or file
Description
bool 
imagejpeg ( resource image [, string filename [, int quality]] )
     imagejpeg() creates the
     JPEG file in filename from the image
     image. The image argument
     is the return from the imagecreatetruecolor() function.
    
     The filename argument is optional, and if left off, the raw image
     stream will be output directly.  To skip the filename argument in
     order to provide a quality argument just use an empty string
     ('').  By sending an image/jpeg content-type using
     header(), you can create a PHP script that
     outputs JPEG images directly.
    
Note: JPEG support is only available if 
PHP was compiled against GD-1.8 or later.
     quality is optional, and ranges from
     0 (worst quality, smaller file) to 100 (best quality, biggest file).
     The default is the default IJG quality value (about 75).
    
     If you want to output Progressive JPEGs, you need to set interlacing
     on with imageinterlace().
    
     See also
     imagepng(),
     imagegif(),
     imagewbmp(),
     imageinterlace() and
     imagetypes().