Oh hey look, blocking artifacts that can be reproduced in pretty much every digital image ever. He doesn't specify what image he used. He doesn't specify what he did to the image. What a joke. But it's in a Youtube video, so Tom believes it.
http://www.iti.gr/files/csvt_10-2002.pdfTHE BLOCK-based discrete cosine transform (B-DCT) scheme is a fundamental component of many image and video compression standards including JPEG, H.263, MPEG-1, MPEG-2, MPEG-4, and others, used in a wide range of applications. The B-DCT scheme takes
advantage of the local spatial correlation property of the images by dividing the image into 8 x 8 blocks of pixels, transforming each block from the spatial domain to the frequency domain using the discrete cosine transform (DCT) and quantizing the DCT coefficients. Since blocks of pixels are treated as single entities and coded separately, correlation among spatially adjacent blocks is not taken into account in coding, which results in block boundaries being visible when the decoded image is reconstructed.
I don't get any of the technical stuff, but I gather that JPEG images are composed of lots of blocks, and the edges of those blocks can be rendered visible.
You'd be amazed what you can learn with a modicum of skepticism and an genuine desire to learn new things.
e: Here is a demonstration of these artifacts that anyone can reproduce:
Step 1: Open MS Paint and open a new file. It doesn't really matter about the dimensions. To make this something like the Apollo images, fill the background with black and then use the circle tool to make a white circle in the middle of the image, like this:

Step 2: Save this file as a JPEG.
Step 3: Use the fill tool to fill in the black space with different colors and look at what happens. You'll see something like this:
