The following's crossposted from the Official Linden Blog:
Welcome to the first day of the rest of your Second Life!
(Post-processed picture taken using the forthcoming WindLight.)
The Client menu is jam-packed with hidden goodies which can help enhance the usability and enjoyability of your Second Life. If you’ve never heard of it before, or consider yourself non-technical and are feeling kind of intimidated already, don’t worry — I’m going to guide you through the highlights of 10 debug options that’ve enriched my day-to-day activities inworld.
Before we go further, I do have to precaution you that doing what I’m going to describe is at your own risk. We don’t offer any support if something goes wrong — some of what’s in the Client menu has sharp edges, and like the knife drawer, that’s why it’s closed by default. So if you’re willing to experiment, please understand that you run the risk of getting cut, but if you feel comfortable with handling these tools on your way to becoming a master chef of the Client menu, then come along with me. 
Quiet Snapshots to Disk -> I have tried that but it doesn't seem to work. I select it and I see then an X next to it, which means it’s on. But then I take the snapshot and I hear the sound and my av does the animation.
Then I'm not sure. Either it doesn't work for some mysterious reason, or it does work such that the other people won't hear the sound, but I do. ???
Hm, I always have Quiet Snapshots on at it works for me. Then again, I always use the CTRL-` shortcut for Snaps too.
I haven't seen me doing the animation when sending to Snapzilla either though.
@Wilhemina: You can reproduce this bug each and every time? Are there finer steps I should know about? Relatedly, Jake Linden recently fixed "Selecting Cancel while saving a snapshot to disk still triggers snapshot gesture" thanks to a patch from a Resident: https://jira.secondlife.com/browse/VWR-1318
Hi, sorry for my delay in responding. You asked me if I can reproduce this bug each and every time. I will keep my eye on it and I'll test more. Right now I have quiet snapshots to disk selected, but I still see the animation and hear the sound. I'll let you know if it continues. Thanks!
How do I jump on stuff?…
If you spend any time at all in Samurai Edo or Meiji or any other C:SI Combat Samurai Island sim you'll eventually find someone standing on yer head. Why? Well it means we love you. And also cuz it's fun….