The pages [1] have a mix of "Images/Graphics by", "Compiled/Written/Created/Contributed By", and "(Fractal) Attributed to" going back to 1990. So I think that attribution refers to the content and not just the page itself.

[1] https://paulbourke.net/fractals/

I take it he claims to have created these particular pictures of the fractal, which is likely true. And yes, the webpage containing them as well.