Some of the coolest ideas I've had have been inspired by cool art in the image file. The very first example are the gargoyles scattered around Metzetli, I won't go into detail since they're kind of deep in and the surprise is the coolest part, but that idea wouldn't have come if the helpers working on the project hadn't found the image and proposed we use it. Another example, also on Metzetli, is the Hellebore. It, and the root, were sitting in the image file, but I had no idea where they had come from or what they were intended for. (Of course, Sunken Colonies from Starcraft have to be given some credit as well.) The latest example are the newly introduced leeches, again, I won't go into details since a lot of people haven't seen it yet, but it was originally intended to be included in Lily Pond 2. I said, "an image that neat deserves a new mechanic", and it eventually became what we've got today. Those three parts of Clan Lord just would not have existed if it wasn't for talented artists inspiring additional creativity. And this is just for images without suggestions, it doesn't include the numerous great ideas we've gotten from artists along with art for them. Artists have a lot of power in that way, they can say: "Awesome Art. Awesome Idea. Now you just do the easy coding, testing, and balancing part."
In short, artists are awesome.