You don't have to be "selling" copyrighted material from another party to be liable for infringement; Using it for any gain, monetary or otherwise, without license or permission, is against the law. If publishing that intellectual property benefits you in any way, such as enhancing your website appearance, attracting new customers, or advancing your career or political aspirations, the creator of that material is entitled to compensation. Make sure that everybody who contributes to the success of your business gets a piece of your prosperity. Secure a proper and legal license or permission from the artist, author, composer, photographer, writer, musician, inventor before you display their work, whether for profit or not, and always give attribution to those who were creative enough to make you notice and be attracted to their creation. Never assume that anything is in the public domain and can be used for free. Be fair and honest. Maybe your lawful exposure of copyrighted materials will catapult the fortunes of everyone involved.