Legal Question in Intellectual Property in Florida

Using an image from the book would be pure and blatant Copyright Infringement and a very bad idea. Dr. Seuss, like Mickey Mouse, protect their copyrights very aggressively.

Whether or not to use a line from the book is slightly more complicated to answer. If the line is being use in some way as a parody, then you may be able to get away with it, otherwise you are probably going to violate the Copyrights. If you believe your use of the line may be a parody, you should seek a legal opinion from an attorney familiar with Copyrights before your proceed.