Compared to other patrols on Wikipedia, file copyright patrolling is severely understaffed, and largely can't handle the number of files uploaded each day. That's why we need the help of AfC and NPP reviewers. A significant number of bad files are uploaded for use on drafts and new articles, so AfC and NPP reviewers are in a perfect position to detect them.
All articles and drafts should be scanned for text copyright violations during review. While checking for text copyright violations, you should also check for file copyright violations.
Basic steps edit
Logos, album covers, movie posters, and other non-free content edit
The non-free content policy allows the use of logos, album covers, movie posters, and other similar image for identificiation purposes in articles. Non-free content must not be uploaded to Wikimedia Commons, and may not be used in draft articles. If you see obvious non-free content on Wikimedia Commons, please request its deletion using the link in the Tools menu. If you find non-free content in a draft you are declining, please remove the images from the article.