problem in showing an img open from zip archive

iam get the img date from the zip archive by getFromIndex() and the date like that (this the first line of text appearing)

‰PNG  ��� IHDR���@���@���ªi

know how i can makke appear iam used

$im = imagecreatefromstring($data);
if ($im !== false) {
    header('Content-Typ开发者_如何学JAVAe: image/png');
    imagepng($im);
    imagedestroy($im);
} 

but its did not worked and used

header('Content-Type: image/png');
imagepng($data);
imagedestroy($im);

but its did not worked and giving me Warning: imagepng(): supplied argument is not a valid Image resource

now you asked me about the date format we assume the output is

$date =  file_get_contents('http://sstatic.net/so/img/logo.png');

the text appear is the same format but i must use $date because i must get the contents first

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I suspect this image data is not the only output of this script, right? But it must be.

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The data already looks like a PNG file (notice the magic number). What happens if you output the data to a file ? Or How about just echo the data and don't call imagepng. Will that work ?