When comparing Eye of Gnome (eog) vs feh, the Slant community recommends feh for most people. In the question“What are the best FOSS image viewers for UNIX-like systems?” feh is ranked 3rd while Eye of Gnome (eog) is ranked 9th.
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Pros
Pro More lightweight than other kde or gnome dependent applications like gwenview, gthumb or kphotoalbum
Pro Double-click to view Fullscreen
By default, double-clicking on the current image opens it in Fullscreen mode. This can be turned off in Preferences if desired
Pro Image Slideshow
You can view a slideshow of all images in the current folder, and adjust the delay between images in the Preferences dialog
Pro ESC key exits Fullscreen and program
Pressing the ESC key exits Fullscreen mode, as well as exits the program ... hence press the ESC key twice and you're out
Pro Can set image as wallpaper
You can set the current image as your desktop wallpaper directly from within this program
Pro Loads up images extremely fast
Pro Minimalistic
Goes well with tiling window managers.
Cons
Con No APNG support
And it won't be it seems https://bugzilla.gnome.org/show_bug.cgi?id=151281
Con Still have gnome dependencies
Con Junky rescaling by default in WMs
Fixable by running these commands:
echo "alias feh='feh --scale-down --image-bg black & disown" >> ~/.bashrc
source ~/.bash_profile
But after entering those two commands for all users, feh works flawlessly, and is extremely responsive. Would definitely recommend.