"Comparison is the thief of joy." Theodore Roosevelt
Don't get caught up in comparing yourself. And I apologize for the people who are rude. Also, don't just think that because people look at you all together, they are thinking you look out of place. That is a feeling you have, not them. (It is none of your business what other people think anyway, you could drive yourself crazy wondering!)
Get yourself in those pictures, you can delete the ones you really don't like and you will regret having none in the future. Practice poses that you feel are more flattering so when the group gets together you know how to pose so you'll like how you look better.
Now, find yourself a hobby or sport you like and focus on that. Be the You that You can be!!
Beauty is only skin deep. Plus we're all going to get old, soon enough we're all going to look alike, wrinkly and dehydrated...lol
Soon you will be living your own life, and not in constant company of your siblings. Enjoy their company now, soon you will all be scattered in the wind. Don't let any unthinking person's comment ruin the time you have left at home with your kid sisters and brothers. It's too special a time. Believe me, they don't think of you in terms of your looks, i'm pretty sure. They love you for what's inside.
There's a good article on Wikihow @ http://www.wikihow.com/Stop-Being-Jealous that might help..
It sounds like you might benefit from considering how you can up your confidence levels. Some discipline like Karate, or yoga, or getting a part time job mowing lawns, or delivering papers. If you have time to constantly compare yourself to others, it probably means you're not busy enough doing what you could be doing to stand apart from others and creating your own identity.
I typed in "how to not be jealous of siblings looks ? and so much great info came up. It'll take time, but i think it would be worth your time to do some reading and make the changes you need from within.
I read this on twitter and I've sent it to a couple of people who were really down on themselves.
Over seven billion people are on the earth, yet not one of us has the same fingerprints, or footprints, or even laugh. Every individual is authentic. EVERY PERSON IS AN UNREPEATABLE MIRACLE.
— Kevin Hall
Really look at this and think about the message. Because it's true. You need to realize that you, me, everyone in this world is special and unique and there's no one else like any of us anywhere in this world. That makes all of us special and amazing. It is our DIFFERENCES that make us special, not the similarities. And as you get older you'll probably find that being individual is preferable because being like everyone else is boring.
It's unfortunate that you feel you must look, act and be just like your siblings. Are their lives any better then yours? What exactly is the problem with your appearance? Is your family making comments or are strangers making comments?
I just hope you get to a point in your life where you embrace who you are and feel good in your own skin without comparing yourself to your siblings or to anyone else.
Unfortunately people like to compare human vs. human and to make matters worse they verbalize the comparisons. Moreover, people can be mindless about the things that say. You in turn are letting this control your life and control how you feel about yourself. Are you going to give these comments all the power? You have the POWER to accept or refuse what people say about you.
You state your siblings love you then why not go out or hang around them and focus on having fun and enjoyment vs.focusing on how you look in comparison to them?
Being envious, jealous and letting people make you feel insecure is a sad way to live. You are wasting time and your life focusing on the negatives.
Get a piece a paper and write 10 positive characteristics about yourself. If you can do that, then I wouldn't worry about this other negative stuff.
People judge by appearance, but the ones that matter are the ones who see beyond how you look and embrace you as a whole person.