loupe (the new core image viewer) is not present in appstream-data for F39 or Rawhide at all at present. It seems like this is because until recently, eog was still controlling the name "Image Viewer" in appstream-data terms: both eog and loupe laid claim to it, but it seems like eog was winning. eog 45.0, which changes its name in appstream terms, went stable in https://bodhi.fedoraproject.org/updates/FEDORA-2023-92fe74aaf6 five days ago, but it doesn't look like the appstream data either at https://dl.fedoraproject.org/pub/alt/screenshots/f39/ or in the packages has been updated to reflect that yet (in fact, though the spec file says the source data is updated weekly, it doesn't seem to have been updated since 2023-09-04, 22 days ago). The consequence of this is that, even though Loupe is installed out of the box, if you go to Software and search for "loupe", it's shown as not installed, and installable only from Flathub. If you don't have it installed for any reason but want to install it, you can't install the RPM in Software, only the Flathub flatpak.
tbh, it's lucky to be updated monthly these days. I'm syncing the mirror now, and will rebuild the metadata at some point today. Fingers crossed loupe appears, otherwise I'll shout here.
FEDORA-2023-b1502b9819 has been submitted as an update to Fedora 39. https://bodhi.fedoraproject.org/updates/FEDORA-2023-b1502b9819
FEDORA-2023-b1502b9819 has been pushed to the Fedora 39 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2023-b1502b9819` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2023-b1502b9819 See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2023-b1502b9819 has been pushed to the Fedora 39 stable repository. If problem still persists, please make note of it in this bug report.