标题（'Content-Type：image / png'）; 不再工作了？

Question

I have tried several times the string in the description. But it keeps outputting a string instead of an image. Link is here http://wenti.de/resize.php .

Source code is below,

$my_img = imagecreate( 200, 80 );
$background = imagecolorallocate( $my_img, 0, 0, 255 );
$text_colour = imagecolorallocate( $my_img, 255, 255, 0 );
$line_colour = imagecolorallocate( $my_img, 128, 255, 0 );
imagestring( $my_img, 4, 30, 25, "thesitewizard.com",
  $text_colour );
imagesetthickness ( $my_img, 5 );
imageline( $my_img, 30, 45, 165, 45, $line_colour );

header( "Content-type: image/png" );
imagepng( $my_img );
imagecolordeallocate( $line_color );
imagecolordeallocate( $text_color );
imagecolordeallocate( $background );
imagedestroy( $my_img );

Is there a workaround without base64 conversion?

Answer 1

Your PHP script is emitting a UTF-8 byte order mark (EF BB BF) before outputting the PNG image content. This marker is probably causing PHP to default the content type to text/html. Your subsequent call to set the header is ignored because PHP has already sent the BOM.

The BOM has probably been placed in your PHP script just before the opening tag by your text editor, because it's saving the file in UTF-8 format. Change the format in your editor to ANSI/ASCII so that the BOM is not written.

Alternatively, you could try calling PHP's ob_clean() function to clear the output buffer before changing the header.