Photos shown in the website demo video and screenshots (the app running on real photos).
All are CC0 / public domain dedications from Wikimedia Commons.

whiskers.jpg: https://commons.wikimedia.org/wiki/File:Domestic_shorthair_cat_portrait_in_grass.jpg  (CC0; Photo by Marko Milivojevic on Pixnio)
fluffy-dog.jpg: https://commons.wikimedia.org/wiki/File:Dog_at_N%C3%B8rre_Vorup%C3%B8r_Strand.jpg  (CC0; W.carter)
teddy-bears.jpg: https://commons.wikimedia.org/wiki/File:Teddy_bear_of_Margarete_Steiff.JPG  (CC0; Tokumeigakarinoaoshima)
black-cat.jpg: https://commons.wikimedia.org/wiki/File:Black_cat_curled_up_on_a_sofa_in_Newcastle_upon_Tyne,_UK.jpg  (CC0; Salwa Farwaneh Dameh)
headphones.jpg: https://commons.wikimedia.org/wiki/File:Audio-Technica_Headphones_(Custom_Earpads).jpg  (CC0; P0lykey)
sneaker.jpg: https://commons.wikimedia.org/wiki/File:Avia_Shoes.jpg  (CC0; Nave do Conhecimento)