All I really need is the grid of colors that make up an image.

I wasn't sure how to access that (made especially hard since I wasn't sure how it was referred to) - but then I remembered the ThousandWords module - it looks at each pixel and then looks at the color for that pixel, and then puts a character down that is colored that same color.
Looking through that code, it uses GD and image->getPixel which is accessed via iterating the pixels (you can get the size of the image from other calls and then use that to know how to iterate) - and then off of the getPixel call, you can get the rgb for that pixel.

That will be enough for me to get the color data from and then run the analys from there.

I have a few thousand pictures now to program this for - hopefully I can get this banged out in the next few days.

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There are some odd things afoot now, in the Villa Straylight.