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 more customizable and feature-rich experience with a focus on a wide range of image formats and built-in tools, while GPicView prioritizes simplicity and speed, making it suitable for users who prefer a straightforward image viewing experience without the need for advanced features.