Thanks everybody, I agree about the background been almost the same color as the cat, in fact I photoshop the image from two cat images since the main image didn´t had one ear , and add the background later for the reference image. I first though of using a pink color or something to give more contrast but was afraid of getting a more "artificial" feeling and after trying several colors I choose that one which came in one of the original images. Anyway, I´ll take that more into account in my next painting. Still need a lot of practice and learn how to give a realistic texture.