[gthumb-list] Forcing "fit" (always) when in full-screen mode ?

["Ronald F. Guilmette" <rfg tristatelogic com>]

I'm looking at groups of pictures that all have resolution smaller
that my monitor.  I'd like to view them in full screen mode _and_
also with "fit" automatically applied to them (always and in all
cases) so that they will fill as much of my monitor as possible.

How can I do this?

Basically, I just want to force the "fit" operation to occur automatically
for each picture I view, rather than having to manually click on it for
each individual picture.

I'm guessing that there must be some way to do this.  If someone could
kindly tell me what it is, that would be appreciated.