The 3 stars in Orion's belt are in one line and very nearly equally spaced, as are the 3 pyramids. The first is a coincidence. The second may be as well, or it could be deliberate because the Egyptians liked it that way. Either way, the "correlation" is meaningless. Of course, the actual distance between the stars on the celestial globe is totally different from the distance between the pyramids; all you need to do is to change the enlargement of the photo to make it match. And, of course, the real distance between the stars in 3D space bears very little relation to the display in the sky.
As for the fact that the have aligned the 3 stars with the pyramids, that is just a matter of turning the photo the right way. The actual Orion's Belt in the sky will turn as the night progresses (like all stars it goes around the Pole Star once every 24 hours). As the seasons change it will also move up and down in the sky. All this means that the display in the sky bears no relation to the pyramids alignment: it varies from minute to minute.
In summary, there is no evidence that this supposed alignment is in any way special. It's simply a matter of aligning 2 photos in the right way.
I might add that there is also some evidence that the Great Pyramid was aligned with the celestial north pole. However, the Pole Star was not in that position when the pyramid was built, because the earth's rotation axis sweeps around in a circle over 26,000 years. This is called the "precession of the equinoxes", and 4500 years (the age of the pyramids) is an appreciable fraction of 26,000.
The Egyptian god Osiris was associated with annual cycles, such as the flooding of the Nile and the movement of stars. This in turn was linked to the Orion constellation, and the Dog Star (Sirius). As a result, it is conceivable that they intended the alignment of the pyramids to reflect Orion's Belt. By similar reasoning, the Seven Sisters (the Pleiades) are very important in Australian Aboriginal Dreamtime stories. In both cases the only implied significance is that people of ancient cultures were interested in the sky, and wove it into their myths.