I would like to decorate a cart for use in a free books initiative I am planning for our school. Our art club is interested and willing to paint and design it. I understand that we can't have them paint covers from books but we'd like to print out book covers and then decoupage them onto parts of the cart. Would that be acceptable? We want to promote the books while respecting copyright! I've printed out book covers to promote books in the past for special events but am careful to not put them online. They are one copy for a limited amount of time. Is this different?
A tricked-out, decoupaged book cart sounds awesome (especially if it comes with free books). A commitment to honoring copyright is awesome, too. And it is entirely possible to do both.
In the spirit of the educational environment that spawned this question, here is an "Assignment" to teach the students about copyright while designing a book cart that celebrates the works it will distribute:
Part 1. Pick at least five books with covers or illustrations that are OUT of copyright this year. For extra credit, look up what year of publication this would be on Cornell's Public Domain Guide (hint: in 2019, this would be anything published before 1924). Make sure you're working from the date the art was published, not when the text was first published! Copy the covers and decoupage to the cart as needed.
This is the "Public Domain" solution.
Part 2. Pick at least five books with covers or illustrations that are IN copyright. Generate your own version of the illustrations with some key details changed: maybe the setting is now your town/city, or the characters look like students and teachers at the school. Make sure your changes say something about the school or the place where you live, as well as the book. Write a paragraph about why you made the changes and creative choices you did. Do not sell your work, and resist posting it online. Just apply decoupage and let the cart wheel around the school, enlightening and educating people.
This is the "Fair Use," solution.
Part 3. Pick at least five books related to an assignment for a class that will be offered as free books. Work with the librarian to obtain a licensed copy of the covers you picked from a service, and make sure that as you decoupage the covers, you are within the terms of what is allowed by the license.
This is the "110 Solution."
My grading rubric for this three-part assignment is based on: verifying the publication dates for part one; the thoughtfulness of the paragraph for part two; and the clear application of the license for part 3.
Ability to demonstrate all three means the cart gets an "A."
Now, this "assignment" encourages maximum use of the legal avenues available for such a project. Because of that, it is a tad complicated. But as the member suggests there is a simpler solution: licensing.
So, if the project depends on a license, make sure you read the terms carefully, print a copy of the license just as it appears when you download the pictures for the project, and plan to make sure the use of the cart stays within the terms of the license.
And with that, whether you decide to go for the copyright trifecta created by the assignment (public domain, fair use, 110), or simply use a license: cart on!
 One of my favorite devices in the world is the book cart. We use them at my law office, where attorneys and paralegals have color-coded carts to tell them apart.
 The numbers aren't as important as the ratio, here.
 For instance, a version of Tom Sawyer that came out in 1980 with new illustrations would have the text in the public domain, but the illustrations--including the cover--would be protected by copyright.
 Based on 17 U.S.C. 107: https://www.copyright.gov/title17/92chap1.html#107
 Like the one mentioned by the member.
 For instance, decoupaging and adding the art to the cart could be considered creating a "derivative work," so make sure that use is not barred by the license.
 Based on 17 U.S.C. 110(a), which allows the "display" of ONE graphic work by a not-for-profit, accredited school for purposes of face-to-face instructions (so long as that copy was properly obtained).
 If anyone uses this assignment, please let me know, and please send a picture (which we will NOT put on the internet without your permission).