Even SVGs take much space.
https://splitcells.net/net/splitcells/gel/test/functionality/n-queen-problem/illustration.svg takes up 37kB, when changes are ignored.
That means, that 1MB can approximately store just 27 of such images. This could create big bloat of the main repo in the future, which may cause problems. It is easier to move such a media repo into the main repo, if such a media repo turn out to be a bad idea, then the other way around.