Problems related to echo in image output of gd Library

Question about gd Library image output and echo & lt ;? Php & nbsp; header (& quot; Content-type: image/png & quot ;); // notify the browser to output images in PNG format $ im = imagecreatetruec gd Library image output and echo problems

Header ("Content-type: image/png"); // notify the browser to output an image in PNG format
$ Im = imagecreatetruecolor (400, 30); // Create a x Pixel canvas

$ White = imagecolorallocate ($ im, 255,255,255); // create a white image
$ Gray = imagecolorallocate ($ im, 128,128,128); // create a gray image
$ Black = imagecolorallocate ($ im, 0, 0, 0); // create a black
Imagefilledrectangle ($ im, 0, 0,399, 29, $ black); // outputs a rectangle filled with white as the background

// If there is a Chinese output, it needs to be transcoded, converted to a UTF-8 string can be passed directly
$ Text = iconv ("GB2312", "UTF-8", "LAMP brothers-no brother, no programming! ");
$ Font = 'simsun. ttc '; // specify the font to copy the font corresponding to simsum. ttc in the system to the current directory.
Imagettftext ($ im, 20, 0, 12, 21, $ gray, $ font, $ text); // output a gray string as the shadow.
Imagettftext ($ im, 20, 0, 10, 20, $ black, $ font, $ text); // output a black string on the shadow.


Imagepng ($ im); // outputs a PNG image to the browser
Imagedestroy ($ im); // destroys resources and releases the space occupied by memory.
Echo "aaaaaaaaaaaaa ";

?>

The echo statement in the last line of the above code cannot be output. why?


------ Solution --------------------
Output! Do not believe that you can use the binary editing software to open the generated image and ensure that there is aaaaaaaaaaaaa at the end of the file.

Since header ("Content-type: image/png"); // notify the browser to output an image in PNG format
Then the aaaaaaaaaaaaa will become part of the image.
------ Solution --------------------
Two different data streams cannot be output at the same time
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There is a way. You want to output an image and display a text. Make the html page. Change the link of the image to the link for generating the image.
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There should be no error