I'm sure it's just me overthinking it, but it feels like the images Cracked through Tranquil appear to tell the complete story of Discord Whooves in the order of uploading.
Cracked is the moment of Discordization, where the Doctor breaks and becomes Discorded Whooves. Shadow shows how his problem became worse over the course of the story. Release is the Doctor at his darkest hour. Secure shows the Doctor in the midst of healing, thanks to the personification of the TARDIS, where the story is now. By this logic, Embrace shows the Doctor finally back to normal, but still wracked with guilt and self-loathing, even as the appearance of the grey pegasus feathers show Derpy's return. Finally, we end with Tranquil. The Doctor and his companion have returned to each other, and all is right with the universe.
Again, I'm sure it's just coincidence, but either way, good job!