I don't know if there is a good way to hide being too thin--with weak arms and forearms like a little kid--but anyway I'm quite certain it is 75% of the reason nothing works out for me online. The funny thing about it, is I've even asked platonic women for help on what I'm doing wrong, but all I ever hear is this: "Oh, your picture is fine, I like thin guys, thin is better than fat, just be yourself" I even tell these advice-giving women to say whatever they think, but still none of them will say I need to gain muscle.

But anyway, what to do about it? The one good picture I have is where I'm wearing a T-shirt and my "little kid" forearms are on display for all to see. Even with long sleeves, though, it's easy to tell I'm just too thin, overall.

I don't think the near-universal rejection rate is because of my face.. I'm not unattractive in that way, and I have had genuine compliments before. There are other things that could negatively impact the perception of my picture, such as posture, body language and such.. all of which are harder for me, since I'm autistic.

TL;DR Is it the thin arms/overall thin body the most likely reason I keep getting rejected? Or likely something else?