A Web site for those with color issues.
Chose an RGB color and Adobe Color CC
will give you a number of harmonious colors.
This site contains over 25,000 pictures of all
kinds, submitted by teachers, students and others.
All pictures are free and properly cited.
Travis has its own category in the Backgrounds section.
A wonderful collection of rare and unique pictures
and images that have been digitized from the
New York Public Library.
The Library of Congress site can be a bit daunting,
but the digital collections offer many good old
photographs, recordings and videos.
You can get lost for hours in high quality
photographs from the past 150 years. Five or six new
photos are added every day. A blog is included with each
photograph where folks provide all kinds of information
about the picture.