1972 - resize Readme images to match text size

Now that we have larger-res images for the Readme they look good even if
the browser is magnified with ctrl-+ (like mine is).

factorial-test.png looks about the same size as surrounding text at
250px wide. Original size is 330px.

factorial.png original size is 450px. So its width should be 340px.

chessboard-test.png original size is 423px. So its width should be
320px.

0 files changed, 0 insertions, 0 deletions