PhotoQt is a simple, yet powerful and good looking image viewer, written in C++/Qt, published as open-source, and completely free. Developed by Lukas Spies
License: Open Source
PhotoQt offers a robust feature set with extensive customization options and editing tools, making it suitable for power users and those needing advanced functionality. In contrast, Eye of GNOME is a simpler, user-friendly image viewer that integrates well within the GNOME desktop environment but lacks advanced features.