The previous post, Recursive Mona, showed an image of the Mona Lisa constructed from smaller versions of itself. One of the things I don't like about that image, and most other 'photographic mosaic' type images, is that the grid structure controlling the sub-images is so visually prominent. Using multiple scales as I did helps to some degree but the regularity detracts from the overall image.
I've tried to improve this by breaking down the squares that require a more detailed rendering into subsquares in a more varied fashion. There are now 5 or 6 different splitting algorithms used to get the sub-components. This reduces the number of places where you see large numbers of consecutive tiles with the same geometry.
Another technique I've tried out is to blend the sub-images into the overall image at their edges. This tends to smooth out the edges between adjacent sub-images so it looks more natural and also has the impact of strengthening the overal global image. Here is Mona again with both of these techniques applied.