at the moment there is no (easy) possibility to check if media on
commons is used throughout the wikipedia projects included into
Wikipedia Check-Usage  is a web based tool which can be used to
check where commons media is used throughout the wikimedia universe.
Also it is able to find "local" duplicates to commons media.
Check-Usage is strongly inspired by Arnomane's check-usage.sh  - a
unix shell script doing mostly the same job. Because this script has
several preconditions to run, like shell access to a unix/linux system
and several programs installed on this machine, I though of writing a
small web based interface. After short consideration I decided not to
write only an interface calling Arnomane's script, but to re-code it
completly. Check-Usage is written in PHP using libcurl.
So if you are interested where 'your' pictures are used - give it a try.
And commons sysops can use it before deleting files which are more than
a few days old. In the past it was often problematic deleting/moving a
file on commons, because doing this the included pictures in other
wikimedia-projects were broken.
PS: Regarding the traffic load: only the text of the chosen image-page
"I worry about my child and the Internet all the time, even though she's
too young to have logged on yet. Here's what I worry about. I worry that
10 or 15 years from now, she will come to me and say 'Daddy, where were
you when they took freedom of the press away from the Internet?'"
--Mike Godwin, Electronic Frontier Foundation