Each pixel will be composed of 256 sub-pixels, arranged 16x16.  This will give 256x spatial resolution, or 16x linear resolution.  Normally, you'd also set size to x16.

Each pixel will be composed of 64 sub-pixels, arranged 8x8.  This will give 64x spatial resolution, or 8x linear resolution.  Normally, you'd also set size to x8.

Each pixel will be composed of 16 sub-pixels, arranged 4x4.  This will give 16x spatial resolution, or 4x linear resolution.  Normally, you'd also set size to x4.

Each pixel will be composed of 4 sub-pixels, arranged 2x2.  This will give 4x spatial resolution, or 2x linear resolution.  Normally, you'd also set size to x2.

Pictures will be generated as specified.