Interesting image. Technically, the diagonal lines are showing up "jagged" This could be because of the method used to reduce the image to the 640 pixels, a compression problem in your camera, or sharpening before you reduced the size of your image, instead of after. 5
It almost looks like a drawing. It's a neat effect, though some people might not care for it. What kind of processing did you do on this? Too bad it's not a Sooners windmill...
This is an interesting image but the compression artifacts are very, very apparent. Image treatment colour is also a bit off. Almost looks like the photo was grunged or something. I do however like the sky gradient from upper right to lower left.