I got the Gurren Lagann Image Board today! And it was so worth it. :) Here are some scans and pictures...
The book is hard-cover, and includes all the images used in the episode 16 ED. There's an interview section between director Hiroyuki Imaishi and Daisuke Kikuchi (artist of the image boards). Imaishi says that the reason he used image boards was that he wanted to bring out atmosphere and the look of the world for Gurren Lagann.
The image boards were also used to establish the color and lighting of certain scenes. They had to be done before the animation stage, so they could avoid having to redraw things. When the script of an episode was completed, Imaishi would tell Kikuchi "I want boards of this and this" or "Definitely draw one for this." Then the image boards would be laid out as the storyboards were drawn, so many times the scenes came out exactly the way they looked in the image boards.
Imaishi and Kikuchi had similar tastes, so Kikuchi was able to bring out the kinds of images Imaishi wanted. They cite various sources that inspired them, like Steven Spielburg's movies. Imaishi thinks the most beautiful shadows in anime he's seen is the coloring used in the third Mobile Suit Gundam movie, and often spoke with Kikuchi about how he wanted to create something like that. Kikuchi also took into account the eras of anime, using more subdued colors for the 3rd arc to reflect anime from the 90's, and trying to replicate the coloring unique to cell animation.
Though, one thing that Kikuchi didn't draw much of was fight scenes, or mecha in general (the image boards skip over the entire final battle). He preferred to focus on the people because he considered them more important in the story, rather than robot anime where its just robot VS robot and all the focus is on the robots' specs and decorations. "In the end, there's no meaning in having Gurren-Lagann exist by itself. Because there are people maintaining it and people piloting it, Gurren-Lagann can exist." So he just trusted Imaishi and animators like Yoshinari with the fight scenes. XD
Anyway, onto the images. Scans are from 2ch, photos are taken by me (sorry for the quality). There's a lot of material in this book, so these are just some of what I consider noteworthy pages.
That's Lord Genome, apparently. o_o
There are quite a lot of image boards of Kamina City used to establish its "look."
The two Kaminas confronting each other. o.o
This has got to be my favorite page. It's Simon escaping from the multiuniverse labyrinth. It got changed in the storyboards, but I'm glad they still used the top image board in the OP. This photo is too blurry to see it, but Simon's got a wicked grin in the bottom one. :D
Apparently Viral's daughter was originally a boy. His wife is also described here as a "deer or gazelle type."
From the Unused Image Boards section. There's a guy who resembles Kamina working with Yoko as a teacher. :O This was drawn before the scenario was completed.
Also from the Unused Image Boards. The epilogue scene taking place on a beach, with Simon still looking young. Up to now, no one but Daisuke Kikuchi had seen these because he'd just kept them on his computer without showing anyone.