Disclaimers are an important protection measure for anyone operating online. If you own copyrighted materials, disclose your ownership to help prevent intellectual property theft.
If you're using copyrighted material that belongs to someone else, don't fully rely on a copyright disclaimer to protect you against copyright infringement claims.
While you can use a copyright disclaimer under Section 107 of the Copyright Act to announce your "fair use" or certain materials, your activities must actually be deemed "fair use" for you to avoid infringement claims.
Getting permission to use copyrighted materials from the copyright's owner is the safest way to use someone else's intellectual property.