Xpiks is only possible because of the awesome open-source projects that power it. Listed in no particular order.
Qt Framework
Qt framework is an awesome cross-platform framework for C++ maintained by The Qt Company and community.
Curl
curl is one of the best networking libraries maintained by Daniel Stenberg.
Zlib
zlib is one of the most commonly used compression libraries in the world written by Jean-loup Gailly (compression) and Mark Adler (decompression).
Hunspell
hunspell is the leading spelling library used in LibreOffice, Mozilla Firefox and Google Chrome.
Exiftool
exiftool is one the best metadata editing applications developed by Phil Harvey.
Quazip
quazip is a Qt/C++ wrapper over minizip/zlib library created by Sergei Tachenov.
FFmpeg
FFmpeg is a collection of video and audio codecs created by numerious contributors.
OpenSSL
openSSL is the most commonly used library for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.
SQLite
SQLite is one of the most used databases that is in the public domain and maintained by Richard Hipp.