Hi! I appreciate your interest! The photograph that you provided was the basis for my pointillism art, yes! However all my work is done free hand and without computers. I believe the sunflower image is in the public domain and is not claimed by any specific artist as well.

I don't have progress pics of the sunflower specifically but here is my IG where I have many in progress shots of my work https://www.instagram.com/taifavre.art/

Thanks again for you interest :)