Save icon as,,, saves damaged PNG pictures/photos

[intersol]

I've tested with several contact icons and for over 90% of them the picture is damaged: it does not fully load in other application or it does load with visible errors inside.

I was able to reproduce the bug only on PNG pictures.

I will attach two damaged pictures.

[QuLogic]

I don't see anything wrong with those first two pictures. The last one perhaps has some discolouration on the middle left.

[intersol]

More details on the 3 pictures: - all 3 looks ok on pidgin message window before being saved - all 3 looks with garbage in: Windows Explorer, Paint.NET, Paint, - only one of them looks with garbage in: PS, PS Elements, Gimp, Firefox. - i've tried to attach these pictures to the contacts in Outlook 2007 and they do not load completely, they show like they weren't completely loaded.

It's clear something is happening with these pictures and I suppose it's related to the save. Do you have any idea on program I could use to save the buddy pictures? - I want to compare them, trillian does not have such an option.

[intersol]

I've managed to find another chat application that can save pictures, Meebo and the problem does reproduce. If meebo does not use libpurple or does not have any other common components with pidgin this could mean that it's a problem with my system.

It's very strange because loading the same PNG images in internet explorer does load them well.

[intersol]

I think it's a MS bug and I've put more details on http://nusunt.eu/wp/software/png-rendering-bug-in-windows-xp-including-sp3/

[QuLogic]

Replying to intersol:

I think it's a MS bug and I've put more details on http://nusunt.eu/wp/software/png-rendering-bug-in-windows-xp-including-sp3/

Were those files all saved in Pidgin? Pngcheck returns an inflate error for 2, 3, 4, and 6.

[intersol]

Yes all were saved with pidgin, latest release.

[QuLogic]

Also, Windows or Linux? And what versions of Pidgin and GTK+?

[intersol]

Tested only on Windows XP SP3 with Pidgin 2.5.0 and GTK 2.2.18 rev a

[datallah]

I can't recreate this with GTK+ 2.12.11 (which includes an updated libpng) - I've tried it with 8 icons and they all seem to be fine (pngcheck also likes them).

Try downloading the updated GTK+ bundle from [the GTK+ site http://ftp.gnome.org/pub/gnome/binaries/win32/gtk+/2.12/gtk+-bundle-2.12.11.zip] and see if that creates better results.

[intersol]

I've tried with the new GTK+ (replacing the one from Common Files). It does not solves the problem and it's instable with Pidjin 2.5.1 (crashes quite fast and in different places).

So in order to test yourself I could send you a set of contacts. Try to cantact me by chat on y: sbarneasorin or gmail/msn with sorin.sbarnea at jmail'dot'com ;) - replace j with g ;)

BTW: from my test it would be quite simple to reproduce the problem because if does reproduce on ~80% of pictures - but it could be related to y! accounts because right now I wasn't able to reproduce it on other account types.

[datallah]

Please get a crash report for the crashing with the newer GTK+ and file a different ticket for it (I don't experience any such instability).

[intersol]

Update: testes with GTK 2.14.4-20081018_win32 and it does not crash but the problem still exists and it's quite easy to reproduce, at least on y! accounts.

[intersol]

Also tested on Pidgin on Linux and the bug does reproduce.

[intersol]

News: I've tested and the bug comes from he fact that yahoo used a damaged PNG file format for his icons. Around 90% of buddy icons are damaged and are not loaded well by many programs. Lucky, pidgin is able to load them ok even if they are damaged.

In order to solve the problem of saved buddy icons Pidgin should recompress the images before saving them. This would solve the problem without reducing the quality of the images.

PS. Requesting yahoo to repair their file format is useless, we can even think that this is just another way of protecting their IM application.

[datallah]

I don't think it is wise for us to be messing with the image data. We save stuff as it is read off the wire, and that really should continue.

It is somewhat surprising that yahoo would be corrupting the image - can you recreate this with the native client?

[intersol]

Yahoo messenger does not let the user save the buddy icon but you can access the cached icons inside C:\Program Files\Yahoo!\\Messenger\Cache\Icon. All icons are there are identical with the ones saved by pidgin.

I've used pngcheck in order to check the png files and it seams that the problem is related to zlib decompression. I'm almost sure that Y! is not going to repair this because their png decompresser is able to handle with the problem like libpng. Still this does not makes the files valid png files and people saving files will wonder why they see garbled images.