Description of Problem:
The standard greeter lets the administrator
provide logo and background images.  The displayed
images do not change (e.g., are not reloaded) when
the files containing the images change.

Steps to reproduce the problem:
1. Set up a logo image for the standard greeter.
2. Use crontab to replace the file containing the
logo image with a different image (in the same
file, or at least a file with the same name).
3. Log out and watch the standard greeter screen.

Actual Results:
The image displayed for the standard greeter logo
does not change until you log in and log back out
again.

Desired Results:
Around the time the underlying image file is
changed, it would be nice if the standard greeter
would detect that change and redraw the screen
with the new image.

How often does this happen? 
100% of the time.

Additional Information:
I'd like to use some kind of dynamic, live data
for my greeter, such as a weather radar image.  I
have crontab all set up with the appropriate
wget's, but the greeter isn't ready to support
this function.