Eye of Gnome (EOG) is a simple image viewing application made for the GNOME desktop. It is a great choice for simple image viewing on other desktop such as Xfce and KDE too.
It differs from the Xfce image viewer gpicview] in two important ways. First, it allows you to open the image you are viewing in another application like GIMP. Secondly, it has the toolbar placed on top of the image instead of under the image.
Eye of Gnome loads fast. You do not have to wait hours before your image appears like you have to with the KDE image viewer gwenview when you are not using it under the KDE desktop.