When comparing Eye of Gnome (eog) vs GPicView, the Slant community recommends Eye of Gnome (eog) for most people. In the question“What are the best FOSS image viewers for UNIX-like systems?” Eye of Gnome (eog) is ranked 9th while GPicView is ranked 13th.
Ranked in these QuestionsQuestion Ranking
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 Multiple windows
When opening multiple images at once it opens every single picture in a separate window.
Pro Functional
It has all the necessary functions that you can reasonably expect from a lightweight image viewer: you can view all the image files in a directory, rotate and save them.
Pro Customizable
Pro Extremely lightweight
And still you can browse all images in a directory.
Cons
Con No APNG support
And it won't be it seems https://bugzilla.gnome.org/show_bug.cgi?id=151281