Girl keeps saying I look skinnier every time I see her....

If she's into skinny guys then she probably is flirting. Otherwise she might just be observing.

That is kind of a odd way to flirt, is it possible that she is being sarcastic? I think maybe she is poking fun at you and it's flirting.

I see this as the same as a guy saying "you look chubby" to his girl friend... you can change for her or tell her to take it of leave it!

Commenting on a guy's weight is flirting?
What? really?
I've never heard that one before, seems more like an observation.
Next time she says you're skinny say "well then as I'm HAWT" that way you'll see her reaction, agrees disagrees, blushes, whatever..

well my ex boyfriend was skinnier every time I saw him...and I was actually just worried about his health...turns out his meds make him annorexic ...and it broke my heart and I tried helping him but he said he liked the way he looked and didn't want to change. I later broke up with him because I started to look more manly then him..and I couldn't take it anymore.

Just commenting, imao. She'd say soething a little warmer if she were flirting. Something like how muscular yu are, or how you are in such good shape...

You should say "No. That's just you getting fatter." Chicks dig playful banter.

Anyway, I can't tell if that means anything substantial or that she has nothing else to begin a conversation with.

I had something similar, when a girl I met, I know her pretty well etc., she wrote to me that I should look for a woman like that - in the picture was some short 150+ kg woman and to do with her - another picture was even worse.("n action") To me that was utter disgusting thing, but I don't know if she was making fun of me because before she never even wrote anything to me.

I think she's making a bit fun of you, maybe you should ask her how to get "less skinny" xD or if she's gonna help you with it :D ofc if she can cook well, to make a bit fun of her - something along those lines. It is very hard trying to understand what it means because it clearly isn't what she means.

Hmmm...make sure your muscles aren't going through atropy. Otherwise that's a little weird lol.
But I'm sure she's flirting, girls rarely commment or compliment guys, so when they do it's usually because they are interested.