I notice as men, we seem to think that as long as we hold our heads high, chin up, sit up straight, and either look into the camera or slightly off camera when taking pics, we're conveying confidence, and this can be true! But often times, we neglect the subtleties of facial expression that would enhance that very same picture.
The slight squint of the eye while looking off camera that can communicate that a man has a relaxed sense of focus to him, or the smirk that says he can be playfully mischievous, or that 'teeth showing-in the moment' laugh, with the right body language that communicates that he is extremely confident.
There's a few reasons why we love to see a full smiling picture, 1 reason is because we can connect to that expression and that expression connects to a good time! Any particular facial expression, done well in the moment, will elicit a feeling about you and your experience. Women are especially cognizant or at least subconsciously in tune with ALL this shit, especially when they're checking out profiles, pictures, etc.
Face-app will only do but so much to help, believe me, I've tried when editing pics. To promote that genuine connection to the emotion you're conveying in the pic, you gotta feel the emotion and move your face to follow.
So disclaimer: Don't overdo any one expression, have variety. The best profiles will show a range, a range of settings, a range of expression, even if you have a common theme to you, there will be a range within that theme. Have fun on your next photoshoot!