The "Color-Me" picture that go from side to side are to big for the paper in my computer's printer for an example I tried printing a Hydra but half of it was cut off.
Ah I should have included instructions on those types of pictures. They are in what is called 'landscape' mode (as opposed to portrait)
When you print one of the horizontal pictures, make sure your print settings are set to "landscape". This will ensure that the picture is printed on the entire paper.
Since each printer setup is different, you'll have to investigate this setting on your own.