I've searched online about this a lot, but I can't find much that applies; I'm not sure if in the newer versions of gImageReader something changed, because in an older issue you mention that the ...

I ran the Fedora 35 gimagereader-qt package (gimagereader-3.4.0-1.fc35.src.rpm) for the first time in several months and had a hard time figuring out how to work it ...