(CNN) -- Your photo-happy friends may be capturing posed group shots and crazy candids at New Year's Eve parties this weekend, but sometimes you just don't want to be photographed.
Maybe you're having a bad hair day, an "I feel fat day" or you'd simply prefer that the whole world (including your boss) not see any racy details.
But now, almost everyone, it seems, has a camera and video recorder in their pocket, thanks to smartphones. We've created a society of constant shutterbugs who love to immediately share those pics on social media for all to see.
So what boundaries and guidelines should we set with our snap- and tag-happy pals?
Anna Post, the great-great-granddaughter of Emily Post and co-author of "Emily Post's Etiquette, 18th Edition: Manners for a New World," has some suggestions tailored to specific events and situations:
Holiday parties, baby showers and group events in general: Be. Here. Now.
Before pulling out your camera, ask yourself, "Am I taking myself out of the moment?"
"Whatever the event might be: funeral, wedding, concert -- you name it, you're there to participate, and being the photographer takes you out of the picture -- literally," Post says. "I remember being at a big rock concert, and I had gotten lucky and got second-row tickets. I was very excited and I was sending pictures back to my sister who couldn't be there, and I just realized that I had missed my absolute favorite song playing because I was so busy taking pictures."
She says to think about your role at the event or occasion.
"If you've been asked to document just for a moment, that's fine," Post says. But if your role is to actually be there, then you can't forget or neglect to participate.
Weddings: Are you a "Facebook scooper"?
Post says that she gets the most photo etiquette questions about weddings.
"It's probably OK to take a photo of the bride coming up the aisle, unless no photos have been requested, which is often the case because it's distracting," she says.
Post also gets asked about posting wedding photos (that aren't from your own wedding) to Facebook.
"You're posting all of these photos to Facebook before [the bride] has even really had a chance to see them herself and experience that moment. I call it 'Facebook scooping,' " she says.
Post suggests waiting to give the bride and groom a chance to put a few things up themselves or allowing them to vet the photos you intend to post.
"Not that they have to approve every photo that goes up," she says. "But the first set ideally should come from them unless you've asked permission to put them up."
Bachelor and bachelorette parties: Have a talk
Even if you personally aren't up to anything lascivious, if you're in Miami whooping it up with a martini in one hand, standing in front of a cake shaped like private parts, you don't want those photos flashed around the Web.
Post says to have a conversation the moment someone whips out a camera. Or even better, a point person should talk with the group all together about the photo-taking policy at the beginning of the night, and then at the end of the night as a reminder.
Post suggests saying something like, "Ladies, if we take photos, these are for us only. What happens in Miami stays in Miami."
"Especially because it is a bachelorette party, and while it might be fun to do that with your intimate friends, the entire world of Facebook, they are not your intimate friends. That's why we make these discernments and distinctions," she says.
First date: Be fun, not creepy.
It's OK to take a photo, "Maybe if people are having fun with their phone, getting to know each other, sharing a photo op," Post says. "But you're certainly not going to turn it into a photo session of that person -- that gets a little bit creepy."
Funerals: Isn't it obvious?
Is it OK to take photos at a funeral? "Certainly not," Post says.
Dinner parties: Don't invite the uninvited
If it's a group shot, the host made a particularly stunning dish or set a beautiful table, "then you could ask to take 'a' photo; otherwise no, put the device away," Post says. "For one thing, a lot of people start taking photos on an iPhone or similar device, and when they start immediately posting to Facebook, it takes them out of that room and it starts inviting people who weren't invited into that room. It really changes the dynamic."
For private events, Post suggests asking the group, "Do you mind if I throw these up on Facebook later?"
When you really don't want photos taken of you
"People taking a few photos as part of a group event is going to happen," Post says. "But when someone is taking a ton, a ton, a ton [of photos], that's when you might say to them -- either jokingly in front of the group, or if they really aren't getting the message, take them privately aside and say -- 'This really isn't my best day. Photo-op will be done in one minute.' "
She suggests treating it lightly at first, and after that, saying privately, "Listen, I know that you're having a lot of fun with it, but I really don't want any more pictures of me."
If they still won't stop, Post recommends literally stepping out of the photo.
When the photos aren't so flattering
Because we have unlimited photo storage and don't run out of film, people are uploading photos to Facebook by the hundreds, even if the photos aren't that great.
"Most people tend to put the photo up thinking that other people will be excited to see it later," Post says. But that's not true for everyone every time.
You can request (and it should be honored) that the photo of you not be posted on Facebook. If the photos have already gone up, Post says, you have two options: If you've been tagged, untag yourself.
Also, she says, "It's OK, if you really don't like something, to ask them to take it down. I would consider that it is much more of a big deal to ask someone to take it down, but you can always do it. I just might not do that for every image under the sun that your best friend posts."
How to look great in photos
If you don't want to be photographed because of insecurities, there are easy tricks to take better pictures: Think of someone or something that truly makes you happy. And remember good posture -- stomach in, shoulders back.
Or do the actor's trick of standing three-fourths toward the camera, one hip and foot in front, hand on your hip.
Practice smiling and posing in the mirror.
If photographed from underneath, it may look like you have a double chin, so lower yourself so that you're even with the camera or looking up at it.
And practice confidence. Chances are you look better than you think.