Mathematical problem

Ok So I find this pattern for Three wishes baby blanket… Its just a simple pattern of knit every row for 35 inches…
I’m using white as the MC

Well I’m taking it to a new level after 4 inches I added 4 rows of baby blue two rows of white and 4 of blue again… continuing with the white now I’m at about 10inches. I want to add something else I was thinking of a teddy bear or butterfly… it would be too dificult not to mention I wouldnt know where to begin… if I did it in blue. So I want to stick with the white but maybe Purl the image into the blanket.

Kate the Cat is the image I wanted How do i figure out how to center her on there or maybe make her a lil bigger.

It will be a throw for a person in a wheelchair so it’ll be bigger than 35" of course. A teddy bear pattern would be better but the cat will do too.