Pixels is the sixth level of Bigger on the Inside prologue.
The 10th Doctor frantically uses controls on the central console.
Tenth Doctor: We need to try and secure some of her data streams, we must contain the damage in any way we can
(The 10th Doctor's appearance shifts to his pixelated form)
Martha Jones: Oh my God! Doctor, what's happening to you?
Tenth Doctor: (Looks down at himself) I don't know, what's happening to me?
Martha Jones: You're all...blocky.
Tenth Doctor: Thanks.
Martha Jones: I mean, how you look is all corrupted. Pixelated.
War Doctor: She's right, you look ridiculous.
Tenth Doctor: Careful old man, you don't look any better. The TARDIS can project anything onto your visual cortex, and the system controlling that has been invaded by the virus. We're all still the same, but the TARDIS is making us look this way to each other. Hmmmm. Making people you see look really strange, maybe the virus was created by the Trickster Brigade to mess with us. I'm still me, you're still you, there are far more important things to be worried about right now.
With a final scream the consciousness of the TARDIS loses control of her core systems. The lights in the control room go dark.
Unknown: Can anyone reach the light switch?
Unknown: Nobody move.
Unknown: If any of you feel a door handle, don't turn it.
Unknown: Found it!
(The lights come up and all Doctors and allies are in pixelated form)
Martha Jones: "..."