Public domain images and their origins:

  Man1.jpg: http://www.publicdomainpictures.net/view-image.php?image=25880
  Flower1.jpg: http://www.publicdomainpictures.net/view-image.php?image=5860
  Flower2.jpg: http://www.publicdomainpictures.net/view-image.php?image=8828
  Flower3.jpg: http://www.publicdomainpictures.net/view-image.php?image=416
  Flower4.jpg: http://www.publicdomainpictures.net/view-image.php?image=38
  Fruit1.jpg: http://www.publicdomainpictures.net/view-image.php?image=3429
  Fruit2.jpg: http://www.publicdomainpictures.net/view-image.php?image=292
  Fruit3.jpg: http://www.publicdomainpictures.net/view-image.php?image=8117
  Fruit4.jpg: http://www.publicdomainpictures.net/view-image.php?image=3418
  Fruit5.jpg: http://www.publicdomainpictures.net/view-image.php?image=3419
  Image1.jpg: http://pixabay.com/en/daffodils-daffodil-field-6207/
  Image2.jpg: http://www.publicdomainpictures.net/view-image.php?image=1004
  Image3.jpg: http://www.publicdomainpictures.net/view-image.php?image=12844
  Image4.jpg: http://www.publicdomainpictures.net/view-image.php?image=20349
  Plant1.jpg: http://www.publicdomainpictures.net/view-image.php?image=5715
  Plant2.jpg: http://www.publicdomainpictures.net/view-image.php?image=10017
  Plant3.jpg: http://www.publicdomainpictures.net/view-image.php?image=3246
  Tahoe.jpg: http://pixabay.com/en/sunset-forest-nature-55392/
  Woman1.jpg: http://www.publicdomainpictures.net/view-image.php?image=3906
  Woman2.jpg: http://www.publicdomainpictures.net/view-image.php?image=26173
  Woman3.jpg: http://publicphoto.org/people/
                young-woman-and-girl-with-poppy-flower-in-hair/

Other images are:

  Copyright 2013 The Chromium Authors
  Use of this source code is governed by a BSD-style license that can be
  found in the LICENSE file.