1_ I hadn't thought of that. To be honest, my main concern was generating the most aesthetically interesting pictures I could. However the "textures" you'd get from optimiing for the last layers would really be just repeating shapes, albeit maybe a bit smaller than you're seeing in my post. Kinda like zooming out.

2_ Oh ok, I get it now. But that's not what the program is doing. I don't generate a vector for the single layer I am maximizing, I generate an image and run the whole CNN from input to that layer, all through. Then I optimize for that layer's output.

Edit to add: As stated in the post, when I "maximize for a filter", the exact function I am maximizing is the average output for that filter over the whole image.