This list of frequently asked questions will be updated as new questions arise. If you don't find the answer to your question here, please don't hesitate to get in touch with me.
PhotoQt is developed as open-source, meaning its source code is freely available to everyone and can be obtained by everyone for free. It is licensed under the GPL v2 or later, meaning that anybody can use and modify PhotoQt, as long as this license is kept (more info on the GPL v2 here). I decided to publish PhotoQt as free open-source software as I have been the happy user of numerous open-source projects myself, and this is a way I can give something back to the community.
Depending on your system you might have different options available. There is an installer for Windows available, and PhotoQt is available in anincreasing number of distributions. You can always compile the latest version from source (instructions here). The latest development snapshot is available on GitLab.
You can find out what version you are running by executing
photoqt --version on the command line, or by checking the About element when PhotoQt is running (default shortcut: i).
An overview of the configuration used for your build of PhotoQt can be obtained either by running
photoqt --show-info from the command line or by clicking on the version number in the About element (default shortcut: i).
PhotoQt uses a variety of image libraries to render and show all kinds of images. The exact selection of supported image formats depends on which library has been enabled when your build of PhotoQt was done, and also on the versions of said libraries themselves. If you are missing some image formats in your build check that your running the latest version of PhotoQt and inform the maintainer who compiled your build of PhotoQt. If you built it yourself, make sure that all desired image libraries are enabled and found when running