memory usage is constant for me, are you sure you are using version 5.2.6 ?

Please try using this CVS snapshot:

  http://snaps.php.net/php5.2-latest.tar.gz
 
For Windows:

  http://windows.php.net/snapshots/

I can't reproduce it using 5.2.7CVS.

I have to admit that my initial bugreport is a litte bit too unspecific. 

The memory problem only occures if the image is "tainted", f.e. taking a valid png and change a arbitrary line in the source. 

This will result in an error like this:
PHP Warning:  imagecreatefrompng(): gd-png:  fatal libpng error: IDAT: CRC error in  ----
and a rapid growth of the memory usage.

Please provide an example image (link to it or drop me a mail).

Seems to be fixed with the newest snapshot. Cannot reproduce it anymore.

not a bug > bogus

I was able to reproduce the Problem with the current release. It occurs if you try to open an image with an crc error.

Reproduce code:
---------------
while(true) {
    print "\nMemory: ".memory_get_usage();
    imagecreatefrompng("anyimage.png");
}

Image:
--------------
http://drahop.de/php/anyimage.png

Run a single pass through valgrind please.

==18171== Memcheck, a memory error detector.
==18171== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==18171== Using LibVEX rev 1854, a library for dynamic binary translation.
==18171== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==18171== Using valgrind-3.3.1, a dynamic binary instrumentation framework.
==18171== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==18171== For more details, rerun with: -v
==18171==

Memory: 104664PHP Warning:  imagecreatefrompng(): gd-png:  fatal libpng error: IDAT: CRC error in /srv/www/htdocs/ak/memtest.php on line 5
PHP Warning:  imagecreatefrompng(): gd-png error: setjmp returns error condition in /srv/www/htdocs/ak/memtest.php on line 5
PHP Warning:  imagecreatefrompng(): 'anyimage.png' is not a valid PNG file in /srv/www/htdocs/ak/memtest.php on line 5
==18171==
==18171== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 96 from 2)
==18171== malloc/free: in use at exit: 7,917 bytes in 15 blocks.
==18171== malloc/free: 13,027 allocs, 13,012 frees, 4,751,157 bytes allocated.
==18171== For counts of detected errors, rerun with: -v
==18171== searching for pointers to 15 not-freed blocks.
==18171== checked 525,192 bytes.
==18171==
==18171== LEAK SUMMARY:
==18171==    definitely lost: 0 bytes in 0 blocks.
==18171==      possibly lost: 0 bytes in 0 blocks.
==18171==    still reachable: 7,917 bytes in 15 blocks.
==18171==         suppressed: 0 bytes in 0 blocks.
==18171== Rerun with --leak-check=full to see details of leaked memory.

==18171== ERROR SUMMARY: 0 errors from 0 contexts

No error. Still bogus.

Did you at least try to reproduce it? I tested it on various machines with the given script and image. It will crash in no time cause it allocates to much memory.

I already said that it was working here.

pierre@ubuntu:~/cvs/php53/bld$ ./sapi/cli/php -r "imagecreatefrompng('http://drahop.de/php/anyimage.png');"

Warning: imagecreatefrompng(): gd-png:  fatal libpng error: IDAT: CRC error in Command line code on line 1

Warning: imagecreatefrompng(): gd-png error: setjmp returns error condition in Command line code on line 1

Warning: imagecreatefrompng(): 'http://drahop.de/php/anyimage.png' is not a valid PNG file in Command line code on line 1

There is no error either through valgrind.

And yes, the memory usage of PHP MM increases as you keep creating errors, but the memory is freed when it exits >> no leak.

If you read the valgrind output you pasted here, you will see that it did not find any error either...

I can't reproduce this either, the memory usage stays at 8208.