It is very unlikely that Gaston Julia saw a computer-generated image of a julia set. The first images were obtained at the beginning of the eighties. Note also that this would have been far less interesting and accurate images than the ones that were drawn by hand at the end of the nineteenth century.

Compare for example the following hand-drawn image of a limit set (so, something slightly different from a Julia set, but not by far) from the book of Fricke and Klein (1897) with the same image generated by a modern computer (which could not have been produced with one of these house-sized black and white computers from the times of G. Julia). You can find more details in this online article by M. Audin and A. Cheritat, in French.

It is very unlikely that Gaston Julia saw a computer-generated image of a julia set. The first images were obtained at the beginning of the eighties. Note also that this would have been far less interesting and accurate images than the ones that were drawn by hand at the end of the nineteenth century.

^{Credit: Fricke and Klein, 1897, hosted by Centre national de la recherche scientifique (CNRS)}

Compare for example the above hand-drawn image of a limit set (so, something slightly different from a Julia set, but not by far) from the book of Fricke and Klein (1897) with the same image below generated by a modern computer (which could not have been produced with one of these house-sized black and white computers from the times of G. Julia). You can find more details in this online article by M. Audin and A. Cheritat, in French.

^{Credit: CNRS}