eog plugin - complete reload from disk of current picture

Hi,

I am writing an EOG plugin and I need to reload the current picture 
because I am going to modify the pixbuf of image and want to undo this 
modification in certain cases.
(The modification of the pixbuf is only for visualisation of "marking" a 
picture, so that this shouldn't be saved or the undo jobs shouldn't be 
used neither).

How can I do so?
In fact, I need the same functionality like the reload plugin from the 
source tree, but this plugin doesn't work for me.


Thanks for your help,
Gernot