I came across this great article on ebookfriendly that listed best quotes about libraries and librarians and then I found myself using BeHappy to create some library quotes
Within our school libraries we need to provoke, to inspire and to get kids thinking even when they think they are not. Quotes positioned in corners of the library or as part of a vignette should be designed to catch the student off guard and challenge them.
Buzzfeed had an article with some gorgeous pictures of old libraries with quotes. I personally wouldn't use these images in my library because they are too book-centric, but I am sure that you could do something similar with these quotes using
BrainyQuotes has some library quotes as well that might be useful or if your space is a commons, there are some equally interesting quotes on information and knowledge.
Or you could try Recite this, which have some different layouts and images.
There are many more online quote generators, but I had a play with some of the simpler ones and also Web 2.0 sites that allowed you to download without signing up.
If you don't have time to play around, check out Etsy for some library quote posters that you can either order as a print, or order as a digital download and then you can print it yourself.