The change is kind of like when Liberty revised the cover art on the first three Chipmunks LPs. They looked like real chipmunks at first, and they were scary with BIG TEETH - the universal indicator that a cartoon character is dangerous. But they were replaced with the cute, non-aggressive Chipmunks that we all know and love.
So that first June Christy cover is like the scary early Chipmunks, and the color replacement is like the cute cartoon Chipmunks.