why do people post pictures on here asking if they're beautiful when they blatantly know they are?

You may be very surprised to learn that in reality, they are asking because they need affirmation. They need this affirmation or positive reinforcement because they are insecure and for whatever personal or psychological reason they truly dont think they are attractive.

In my experience the most beautiful people are the ones who have no idea how others see them.

beauty is indeed in the eye of the beholder despite our world media attempting to make us believe everyone likes only one type of haircolor or bodytype. For every chubby or large guy and gal out there, there are just as many who find extra padding on the opposite sex to be absolutely arousing and extremely attractive. For everyperson who loves a blonde there are just as many who love brunettes. For every older woman who thinks men are only attracted to younger women there are actually more men who prefer a woman of maturity experience and intelligence, for every young pretty 20something girl who dates big or overwieght hairychested guy it doesnt mean she is only after his money, she may be a fan of big guys and hairy chests and he may be broke,

people ask if they are attractive because they want either A)affirmation and reinforcement or to be told yes to feed their insecurity or B) they ask because they want constructive criticism and want to improve

you may think these people who ask are beautiful for sure soo much that they in your opinion couldnt possibly not know theyre pretty- however the truth is they ask because they are insecure and not everyone likes their look in all factuality they are insecure for a reason, someone told them they werent pretty

Are you saying that you, yourself are ugly and fat? o__o

Well, maybe they hear it from people that they're pretty and stuff, but they won't believe it. Like they need to be constantly be reassured that they're beautiful. Self conscious, I guess.

I know that I had to be told that I was pretty like a bazillion times from my girlfriend before I even started to remotely believe it.

to show off,, they need their egos boosted,, I was wondering that too! they are like,, do you think I am beautiful ? could I be a super model? oh by the way do you think I am handsome ? hahahahahahaha

not all of them are that beautiful, they're full of themselves, genuinly curious, or need an ego boost (you do too by the sound of it)

To feel better about themselves...so people like to hear that they look good!

because they are stupid and cant understand how good they look

or

they just want us to tell them no i think your hot so they can have even more people then the ones around them tell them that

oh i know they are so bloody self centred and vain, does my head in " how gorgeous do i look" rate my face" rate my vain self obsessed ego"

who cares what they look like

Ego boost, perhaps?