here's a good illustration of the hollow earth theory north/south-pole holes:
scroll down a little more than half way to see it (look for "North Polar Opening"):
Voyage to Our Hollow Earth
the "hole" is said to be about 1100 miles in diameter.
but that's just where it starts curving
the actual passageway into the other side is only about 90 miles wide.
look at this picture and remember this:
1. the poles are usually covered in very dense cloud.
2. there's ice and water all around that opening.

by my rough estimate (holding up a piece of paper to the screen and drawing lines), there's only a window of 30 degrees at which you could actually see through the hole into the interior of the earth. that window is a cone, centered on the axis of the earth's rotation. in order to see that, you'd have to be in an orbit at maximum 15 degrees from the north pole, and be able to see through the cloud cover on this side (plus the purported clouds on the interior).

here's some pictures, but i think they're really poor and don't indicate much. just here for fairness.

now, keep in mind that we've only got a few illustrations of this. the actual measurements of this thing could be totally different, if it exists.

i think that most spaceship activity occurs away from this 30 degree region of the poles. spy satellites, communications, weather, it's all focused around civilized places. the stuff in that 30 degree region would probably be way more classified.
just conjecture..

to sum up, most pictures of this region, if the hollow earth theory is correct, will be an optical illusion of an unbroken spherical earth.