In Linux, you might want to take a look at a program called
gThumb, an image-management
application that in several ways nicely complements
GIMP. In gThumb,
you can cause an image to open in GIMP
either by right-clicking on the icon and selecting
GIMP from among the list of options, or by
dragging the icon into the GIMP toolbox.
See the gThumb home page [GTHUMB]
for more information. Other similar applications are : GQview
[GQVIEW], XnView
[XNVIEW].