Isn't that just like distributing object code? The more detailed
image could (in some respect) be considered the source code.
Source code and object code are qualitatively dissimilar, and it is
nearly impossible to understand or change object code. By contrast, a
larger image and a smaller version are qualitatively similar: a person
can directly see both, and can edit both with the same tools. So the
analogy is not a good one. The smaller image is not as desirable as the
larger one, but it can be entirely free.