We tend to see the ones we love through rose-colored glasses - we don't notice the bad photo, only seeing the pet we adore. Chances are you've got a shot not much different from the one on the left of your pet: too close, flash, and a less-than-happy expression. If you're going to devote hours to creating a drawing from a photograph, you need to look objectively.
To begin with, try to enlist a family member or two to help with your photography session. Instead of your pet peering down the lens as in the first example, your helper can distract them away from the camera, so that you can get a three-quarter or profile photograph from a good distance.