When we look at the horizon from the surface of the Earth, it looks perfectly flat, therefore we can certainly deduce that the Earth is not a small ball. But does this prove that the Earth is completely flat on the big scale?
If you look at a small circle, you will see a sharp curvature, but if you see a big circle, for example a circular building or a park, the edges will look almost flat. The bigger is the diameter, the more flat the curve appears. And when we get a bigger and bigger circle (or a sphere), it comes to a point where the curvature becomes unrecognizable. At that point we are not expected to see the curvature.
Earth is so big (12 000 km wide) that we cannot see the curvature. Even airplanes are not flying high enough (10 km high) to show a clear curve. The Earth is too big and we are too small. And it’s not easy to get far away from Earth enough to see a clear curve. Therefore it is not smart to “debunk” globe by showing the flatness of the horizon in photos made close to Earth’s surface. But it is smart to show the pictures from space to prove that the Earth is a globe.