GD Error on displaying png image

[Xiao Tencas]

When trying to load a png image in GD, I get the error (Mozilla Firefox)
"cannot display image, because it contains errors"; IE just shows an empty
'image-error' box.
When loading a large enough image, it does build up the image
gradually until it's almost finished, but then the partly visible image
is replaced by the error message/error box as described above.
It seems like indexed <256cols pngs are not subject to this problem. I've
read that earlier versions of GD were limited to handling indexed pngs
only, but recent GD versions (>=2.0) should not.

My configuration:
GNU/Debian Linux 3.0, Apache 1.3.31, PHP 4.3.4, GD 2.0 'or higher'
(bundled with PHP), libpng12-0 1.2.5.0-7,
Also tested on GNU/Slackware Linux 9.0 with Apache 2.0.49, PHP 4.3.6,
GD 2.0.22, with similar results.



The testcode I use:
<?php
$photo = "image.png" ;
$im = @ImageCreateFro mPng ($photo);
header ("Content-type: image/png");
ImagePng ($im);
?>

Anyone got a clue? Thanks in advance.
Wim

[Andy Hassall]

Re: GD Error on displaying png image

On Sun, 29 Aug 2004 16:52:40 +0200, "Xiao Tencas" <xiao_tencas@gm x.net> wrote:
[color=blue]
>When trying to load a png image in GD, I get the error (Mozilla Firefox)
>"cannot display image, because it contains errors"; IE just shows an empty
>'image-error' box.
>When loading a large enough image, it does build up the image
>gradually until it's almost finished, but then the partly visible image
>is replaced by the error message/error box as described above.[/color]

A wild guess; how long does the image take to download? Is it exceeding the
setting of max_execution_t ime? This would dump an error message in the image
data and so could cause this symptom.

--
Andy Hassall / <andy@andyh.co. uk> / <http://www.andyh.co.uk >
<http://www.andyhsoftwa re.co.uk/space> Space: disk usage analysis tool

[Jeffrey Silverman]

Re: GD Error on displaying png image

On Sun, 29 Aug 2004 16:52:40 +0200, Xiao Tencas wrote:
[color=blue]
> The testcode I use:
> <?php
> $photo = "image.png" ;
> $im = @ImageCreateFro mPng ($photo);
> header ("Content-type: image/png");
> ImagePng ($im);
> ?>[/color]

No clue. But to debug GD images, you can change the header to
"Content-type: text/plain" temporarily. This will dump the contents to the
screen as plain text, including error messages!

--
Jeffrey D. Silverman | jeffreyPANTS@jh u.edu **
Website | http://www.newtnotes.com

(** Drop "pants" to reply by email)