Interlaced PNG does not load: Error message.

Hello,

The PNG image included (1.png) does not load on my computer in Filter Forge 4.002 standalone on Windows 7 32 bits (Home Premium SP1, English). Whereas other PNG images are ok. My laptop has an Intel cpu and for its graphics hardware: ATI Mobility Radeon HD 4300.

The error message in Filter Forge is: "Unknown Bitmap Storage Format in File '[...]1.png' (0 was expected)."

I produced the 1.png image included here with PhotoFiltre 6, saving the image in PNG with Filter type set to "Average" and Interlaced selected.
Windows Photo Viewer and Paint load the image flawlessly.
Other similar tests have shown that the issue seems to be with Interlacing, not the filter type (I tried "Average", "Paeth", "Up" alone and it worked - whereas it did not when Interlaced was selected).

Great software, by the way (a bit of marketing on mainstream download sites like softonic - and per country as well -, could help, so - it was not that easy to discover Filter Forge, honnestly, despite the amazing possibilities it offers).

Best Regards

Hey, I just checked, this issue can be reproduced as well for interlaced pictures from the the set of test PNG files found here:
http://www.schaik.com/pngsuite/pngsuite_int_png.html
(first page here: http://www.schaik.com/pngsuite/ )

The image basi6a16.png leads to the same error (when Firefox 17, Windows 7 and other utilities display it correctly).

Well, it's a bug in libpng that is not fixed in Filter Forge. Like you mentioned updating libpng would fix this issue (but it could introduce new bugs).
But it is not a limitation in libpng, that's a bug, see here and there:
http://stackoverflow.com/questions/12...read-image
http://sourceforge.net/p/libpng/bugs/165/

Since many softwares do use tons of third party libraries or interpreted languages, not counting this as a bug is not going to thrill potential bug hunters, that is for sure.