Hi, some PNGs released with KeePass have problems with the combination of recent versions of Cairo and libpng (which are used by Mono). This leads to a crash when building KeePass with Mono. The bug in cairo is quite subtle and it's being fixed, but the solution might not come in the near future. In the meantime it would be very helpful to produce a version of those images that don't raise the issue with cairo/libpng.
The PNGs are those under "KeePass/Resources/Images/", the others work fine.
The workaround we found is to run pngcrush on each image as follows:
pngcrush -ow -c 6 image.png
The "-ow" parameter overwrites the original file and "-c 6" change the color_type to ARGB, while they currently are RGB. There are probably other tools available to do the same thing. Note that although this fixes the problem, other RGB only images work fine (e.g. KeePass/Resources/Nuvola_Client/C67_Certificate.png).
On the Gentoo bug tracker you can find additional information on the problem (such as references to cairo bug tracker) and this temporary solution.
Thanks in advance.