I used some images that I found online to feature in my app design. I have chosen to feature photographs of the eyes of different animals in my app design as a form of link to each page within the app; When an eye is selected it would load up the page with the information regarding that particular type of animal. Below are the links to the sources.

Dog: http://pets.thenest.com/eye-allergies-dogs-7084.html

Cat: http://www.lightstalking.com/cats-eyes/

Fish: http://www.coolanimalworld.com/page/11/