As much as I love this site, I will admit I feel uneasy about posting pics with my face in it. My biggest fear is that someone uses that face pic to, I don't know, stalk me, post it elsewhere on the internet, other horrible stuff. I know most people on this site are the not the kind to do it, but you honestly never know. I know those lessons you learned in school about internet safety were probably too overprotective, but you have to admit they have a few good points.
So my question is: how can I trust someone to privately share my pic with them? Should I even share my face in the first place? And for those who do post pics with your face: how do you feel about this? What do you guys think?

I don't know your situation. I share photos with my face in them all the time, and I have for over 20 years. So far, no stalkers.

However, if you're a celebrity, or someone who's career could be ruined by some random photo, then it's not safe to share a photo with someone privately unless you really know that person and know they won't share it on-line ... like your mother, maybe.

Again, I think the danger is over-hyped. There are 7 billion people on this planet, do you really thing you photo is all that special? If it is, obscure your face with something.

That's 4 questions actually but I'll go through them one by one.
TL;DR - Be yourself, and protect yourself. Be as open as you feel comfortable being.

1. The word trust comes with a lot of connotations and similarities in many languages. Some of these are truth, faith, belief, promise. Trust in our society tends to be given to those whom we know on an intimate (close personal) level. For instance, most of us with good relations with our parents at least, TRUST our moms and dads. They hopefully taught us right from wrong and a myriad of other things we needed to know to become decent human beings.

Someone on the internet isn't someone you know. So in this case, "trusting" them is putting your 'faith' and 'belief' in them that they will 'promise' to keep something between you. I can't answer that question because I'm not you. You and I do not have the same levels of faith because our experiences are different. YOU have to answer this one yourself.

It's also fair to point out that while I don't mean anyone harm, I have accidentally betrayed someone's trust through miscommunication. That has happened, here. I lost a friend for it, and it makes me feel bad a lot.

2. Do you feel the need to share your face? Ask yourself why you feel you may want to. The answer for me has to do with my reason for being here. Finding WAM/sploshing on the internet was a HUGE discovery for me. It showed me that there were other people that felt and/or thought the same way as me. I decided I wanted to connect with them, on a very personal level. I wanted friends, real friends. So I realized that while it's important to protect ourselves, in order to do that, we have to drop our guard and show who we are. So I decided to show my face.

3. Much better now than I used to. This is mostly because I am a person with anxiety, and for most of my life I didn't know it was abnormal, and was left unchecked. Now I'm medicated. I understand the reasons for not wanting to show our faces. It gives us a certain level of anonymity and protection. Furthermore, since you haven't met me, you have no way of knowing if my pictures even ARE of me. This is skepticism, also totally natural. I also realized I have a lot less to worry about than many others. I'm a man, we get harassed a LOT less than women. I'm not a public figure, nor do I have a job that I would have to worry about being "found out". I'm not (conventionally) worth anything. So if someone steals my identity, they're not getting much.

4. My conclusion is that you need to carefully weigh your reasons for wanting to do so with the possible benefits of doing so, against the reasons for not. What do you want to achieve here?

If you feel anxious about it, if you feel it would put you in a compromising situation, then DON'T DO IT.

However, the benefits are many fold, including showing others that you are a real person. People will learn who you are, what you like, and dislike.

I know it's a wall of text, but I think it's an important issue.

Warning Addendum - There have been a lot of people here that pose as something else. Fake accounts, people using other people's accounts etc. This has happened with a producer in our community recently even. Be anonymous, or be you, DON'T be someone else! It will NOT be tolerated.

I have only summoned up the confidence to post pics and video in the past couple of weeks, and it's been fun so far. For a kink I kept to myself for years, the interactions that have come from posting about it have been pretty satisfying.
I could understand the worry in some careers, but I'm a local-level musician in a scene quite tolerant of eccentricities, so figured I was unlikely to have problems there. It is unfortunate that any group other than cis men are more likely to receive the undesirable end of online interactions though, and I'm aware of my privilege there...

TBH, It is something I worry about sometimes. MY main worry is showing a clean face pic to someone and then us realising that we know each other outside the messy world, and that may make things a bit awkward between us.
I know that's probably a silly fear and, even if that did happen, would unlikely have huge consequences, but it is a worry that runs around my mind a lot. Especially as, outside the messy world, I'm a comedian. I often wonder if I'd ever meet a fellow messy comedian on the circuit and wonder how we'd both deal with knowing each other's dirty secret, or even if other comedians found out about me being into WAM. TBH, it is a subject I have talked about on stage (though not in any great detail) so I'm likely worrying about nothing.

So another thing you guys can do is post a pic in your profile that isn't your avatar. This has two benefits.

2. You can have a pic of yourself up without being immediately recognizable just from your avatar.

1. If you write a review or do have something that shows outside being logged into the UMD, it will show your avatar that isn't your face.

I usually use do this, and have that potato avatar up so I can write a review if I want. This way if someone on my FB for instance were to reverse image search one of my pics they wouldn't see that it's my current avatar here. But I'm not real worried about it, and this allows people that were on the trip to recognize me.