Tried it when my Image Viewer (Xviewer) startedshowing darker images for the normal ones. Found the same issues here too.
Right-clicked, from Nemo, a directory to open, gave error "/(directory) can not be opened". Opening single file worked.
Gwenview has been a reliable friend for years, but there are one or two problems recently. In Mint 17.3 I had to run sudo apt-get install kdelibs-bin kdelibs5-data kdelibs5-plugins to get it to open jpegs. In Mint 18, kipi plugins not there - sofar.
The best! Easier to crop selected part of multiple files. TQ to those involves in this software
I like very much the full screen browsing of images. Better than the Windows default program.
It handles icc profiles! I am using it in Mint Mate instead of gThumb because this one doesn't read icc embedded profiles
A pretty slick app sadly tarnished by bugs (Mint KDE Petra). Beware as it sometimes shows images incorrectly (compared to other apps) such as too dark/red etc; also fatally crashes persisting until a reboot! GThumb currently suffices nicely.