thumbnail script

problems with thumbnail script implementation

[sharyn]

Platform : Windows XP pro
Server : IIS
PHP ver : PHP ver 4.3.6 with GD

I am trying to implement "Thumbnails in PHP by Michael Bailey" into my own code and I can't make a thumbnail. I get the "broken image" image and when I right click on it to view image I keep getting this error :

Warning: Cannot modify header information - headers already sent by (output started at c:\inetpub\wwwroot\clickreturn\Thumbs.php:8) in c:\inetpub\wwwroot\clickreturn\Thumbs.php on line 85

The error occurs on the line in Thumbs (Michael's code) that says
header("Content-type: image/jpeg");

It's also followed by garbage that looks like this :
ÿØÿàÿþCREATOR: gd-jpeg v1.0 (using IJG JPEG v62), default quality
plus a bunch of other junk

Michael's code can be found in the link above and my code that calls it looks like this :

 printf("<tr>
 <td><input type=\"checkbox\" name=\"checkbox".$myrow['MapID']."\" value=\"checkbox\"></td>\n
 <td><a href=%s?Map=%s&MapID=%s&Lat=%s&Lon=%s><img src=\"Thumbs.php?Maps/%s\" border=\"0\"></a></td>\n
 <td>%s<center><a href=%s?Map=%s&MapID=%s&Lat=%s&Lon=%s>%s</center></font></td>\n
 <td><center>%s%s</center></font></td>\n
 <td><center>%s%s</center></font></td>\n
 </tr>",
 $_SERVER['PHP_SELF'], $KW, $myrow["MapID"], $Lat, $Lon, $myrow["MapFilename"],
 $fontset, $_SERVER['PHP_SELF'], $KW, $myrow["MapID"], $Lat, $Lon, $myrow["Keywords"],
 $fontset, $myrow["Latitude"],
 $fontset, $myrow["Longitude"]);

Thanks in advance for anyone that can help me make thumbnails on the fly

[edited by: jatar_k at 7:42 pm (utc) on June 16, 2004]
[edit reason] delinked [/edit]

[IanKelley]

You need to check out line 8 of the script and remove whatever is outputting to the browser at that point.

[dcrombie]

The script receives one parameter which corresponds to the relative path of the full-size image. This address is to be placed as the src field of an image tag. An example image tag might look like this:

<img src="/thumbnail.php?dir/image.png">.

[sharyn]

Ian,
Thanks for the reply. I found the problem. It turns out that you can't have ANY spaces or even blank lines in front of the first "<?php" in the Thumbs file or else it outputs something before the "header" call. I removed the blank line and all of the echo statements and it works like a champ!

- sharyn

[edited by: jatar_k at 7:41 pm (utc) on June 16, 2004]
[edit reason] removed url [/edit]

[IanKelley]

That's right, anything PHP sees outside of PHP tags it assumes you want sent to the browser. Headers are automatically sent before the first browser output and can only be sent once.

[dcrombie]

...unless you use PHP's output buffering option - but that's another story ;)

[sharyn]

DCrombie,

I tried buffering, but it didn't seem to work. I could have done it wrong though