That's a cool idea. However, I wonder about the utility of a test image that's smaller than most interpolating kernels. The image will probably get mirror-padded, so that's not a problem. But the higher-order (bigger footprint) kernels give a better truncated approximation of the sinc function, the ideal interpolator. Maybe I'm overthinking this. I'll run the experiment. The higher-order interpolators do give better approximations of the original analog signal. That's pretty much a given.