I respectfully submit that you could talk to someone on forums like this for months, perhaps even YEARS and never have an inkling of what they look like. So, you get to know them through the conversation. You like the way they put sentences together. Their ideas make you think. Maybe in your mind you have a mental picture of them. Then, by chance, you get to meet the person and find out that girl you've fallen in love with is a 45 year old guy who is 5 foot 2 and the last time they exercised was a PE class back in High School. Do you not even want to be friends (fair cop IF the person intentionally deceived you...) Or the guy who wrote you love poems for 2 years and who you envisioned yourself marrying is missing a leg and lives with his parents because he'll never be able to hold a job due to PTSD (related, perhaps, to that missing limb) and he looks nothing like the guy you fell in love with in your head. But the reality is, the beautiful person you fell in love with is still inside that imperfect body. Do you walk away from two years of friendship/courtship because all you care about is finding someone who is going to make other people envy you when you're out and about, or do you realize that what you really want in life is someone you can have an intelligent conversation with?
Even if someone shares a picture, you don't know if it's really them, or how old that picture is. Fall in love with some's mind, with their wit, with their kindness and compassion. Looks can fade or be changed in the blink of an eye via tragedy. Physical expressions of affection can be impacted by so many factors. If you decide who to love based on someone's physical presence, what happens when you're 65 and the person you're with is a boring old twit who doesn't really give a shit about you?
Cultivate friendships, find people who truly care about and support you, and if one of those people ends up being the love of your life, so much the better.