I have repackaged
fbshot so that it can be invoked as a stand-alone command from the contentlister. The screenshot is taken 30 seconds later, to give you time to get back to the screen you want.
Unzip the attached file and copy the fbshot directory into (say) the Programs directory on your CF card. Select fbshot from the contentlister to take a screenshot. A bit more than 30 seconds later, it will be in Programs/fbshot/shot with the current date and time in the filename.
I have only tested this on a CF card, but it should work anywhere you normally put contentlister based programs. For debugging, the stdout/stderr of the last invocation of the fbshot command is in Programs/fbshot/fbshot.log. If a 30 second delay is too short, change "-s 30" in run.sh.
The easiest way to access these files is probably via usb connection to a desktop, although mrxvt and emelfm2 can also access them.
I enclose two screenshots (contentlister in Programs directory, and FBReader). These do not do justice to what is on the iLiad screen (particularly for text), but this has always been a problem with fbshot.
EDIT: the screenshots are ok, but even when opening the thumbnails on a large screen the image may be rescaled by your web browser. Click on them again to get the full size and full quality image.