Smaller.
At least according to this link. Silver halide crystals are 0.2-2 um. Where the "dye cloud" is 1-10 um. Pixels on the R5 are 4.39 um, for example.
That is a good way to look at it. Silver halide crystals are in the wavelength of light size.
BTW....that seems to be a pretty comprehensive article. It looks like it may answer a lot of my questions. I've just scanned it for now, but in talking about resolution, they seem to be settling on the 1.6:1 contrast values I've seen represented from MTF curves, not the 1000:1 contrast. For Velvia 50, for example, that would be 80 LP/mm or 22.1 MP FF equivalent/60 MP 645 MF equivalent.