A very nice start, @Harrison Totty, Welcome to the Community ! I have two questions:

• Why are you wrapping Image[GraphPlot[...]] ? It seems to me that just GraphPlot[...] is much faster because no time is spent on rasterizing Graphics into an Image.

• GraphPlot[m] generates a plot of the graph represented by the adjacency matrix m. But adjacency matrix should be square, and a CellularAutomaton can generate non-square matrices. You can see it is true from code error messages:

      AdjacencyGraph[CellularAutomaton[54, {{1}, 0}, 4]]
  

  So then what does GraphPlot[CellularAutomaton[...]] represents in general non-square matrix case?