The fact that some guy taking a selfie on Mt. Everest used a fisheye lens is not exactly a devastating argument against the Earth being round - if some idiot used the photo as "proof the Earth is round" then yeah you've got proof that they're either an idiot or it's a joke you're not getting, but that doesn't exactly prove anything.
But what you do have there is a compelling argument against every flat-Earther who asks "why can't we see the curve?" - I mean, anyone can tell them that at relatively low altitudes there really shouldn't be much of any visible curvature, but this is a really good illustration of how low your expectations should be for e.g. the curvature in weather balloon photos.
Actually LADBIBLE used this photo on Facebook along with an article to say this was proof the earth is round.
I've seen video footage from several sources of weather balloons past the 110,000 foot mark that shows no curve. Also there is the Red Bull sky dive from space footage that gives a great example of both fish-eye and non-fish-eye lenses at the same altitude, fisheye lens is the only way to produce that curve.
On both points, you're not addressing what I've actually said and are repeating the things I was addressing in my comment. I'm not going to repeat myself.