Non-free content must meet certain requirements before they are uploaded.
Copyrighted non-free images are useful, so they are allowed under fair use if they meet certain conditions. They are laid out in a policy known as the non-free content criteria.
Make sure your image doesn't fall under one of these common failure points:
Replaceable images: The first requirement for non-free images is that there is no free-content equivalent for it. Things like photographs of living people, diagrams, charts, and graphs can be replaced by free content, so they fail this requirement.
Articles only: The seventh requirement says that non-free images can only be uploaded if they can be used in at least one article. The ninth requirement says that non-free images can only be used in articles. Articles are pages in the main namespace other than disambiguation pages or redirects. Submissions to articles for creation and user sandboxes are not considered articles for these requirements.
