Photo credits (all sourced from Wikimedia Commons, freely licensed):

helmet1.jpg / helmet1_thumb.jpg — "Calico Cat named Helmet 01" — CC0
  https://commons.wikimedia.org/wiki/File:Calico_Cat_named_Helmet_01.jpg
helmet2.jpg / helmet2_thumb.jpg — "Calico Cat named Helmet 02" — CC0
  https://commons.wikimedia.org/wiki/File:Calico_Cat_named_Helmet_02.jpg
kevinbunny.jpg / kevinbunny_thumb.jpg — "Kevin and Bunny" — CC0
  https://commons.wikimedia.org/wiki/File:Kevin_and_Bunny.jpg
zingy.jpg / zingy_thumb.jpg — "Zingy cat 03" — CC0
  https://commons.wikimedia.org/wiki/File:Zingy_cat_03.jpg
sleepy.jpg / sleepy_thumb.jpg — "The sleepy ones" — CC BY-SA 4.0
  https://commons.wikimedia.org/wiki/File:The_sleepy_ones.jpg
kittens.jpg / kittens_thumb.jpg — "A cat with her kittens" — CC BY-SA 4.0
  https://commons.wikimedia.org/wiki/File:A_cat_with_her_kittens.jpg
tortie.jpg / tortie_thumb.jpg — "High content black tortie" — CC BY-SA 4.0
  https://commons.wikimedia.org/wiki/File:High_content_black_tortie.jpg
talking.jpg / talking_thumb.jpg — "Talking Cat" — CC BY-SA 4.0
  https://commons.wikimedia.org/wiki/File:Talking_Cat.jpg
bed.jpg / bed_thumb.jpg — "Domesticated brown-and-white-coloured feline lying on her side on a bed" — CC BY-SA 4.0
  https://commons.wikimedia.org/wiki/File:Domesticated_brown-and-white-coloured_feline_lying_on_her_side_on_a_bed.jpg
paw.jpg / paw_thumb.jpg — "Macro of cat's paw" — CC0
  https://commons.wikimedia.org/wiki/File:Macro_of_cat%27s_paw.jpg

Resized/recompressed from the originals for web delivery; no other modifications.