Facebook expects all users to comply with certain standards, both in regards to their written words and the photos they post. If you see a photograph that is sexually explicit or violates another of Facebook's rules, report it using the "Report This Photo" link beneath every photo. Facebook will review your claim and take action if needed, including the removal of the photograph.
Facebook reviews each report of an abusive photo to determine its validity. The website administrators evaluate the photograph in question to see if it violates one of the Facebook community standards. Community standards prohibit the posting of photos that include the promotion of self-harm, hate speech, vandalism or theft of intellectual property. Images with graphic violence and sexually explicit content are also a violation of Facebook rules.
According to the Facebook policy on photographs, if Facebook finds an image in violation of the site's rules, it will be removed from the site. Facebook does not request the owner's consent prior to removal of the photo. If Facebook finds the violation extreme enough, it will disable a user's entire account immediately because of his photograph without warning. If the photo's owner believes his photo did not violate Facebook's rules, or his account was hacked and he did not post it, he must contact Facebook to ask for his account to be restored.
While Facebook notifies the users whose photos it deems abusive, your identity is kept private. Facebook will never disclose to a photo's owner or publisher that you were the one to file a report claiming it was inappropriate. Facebook's policy protects you from retaliation from the person reported, so you can feel comfortable creating a report, knowing your part in the matter is kept secret.
What seems offensive to you may not actually be a violation of Facebook's rules. If, for instance, a friend posts a photo of you that is extremely unflattering, Facebook will not take it down if it doesn't violate Facebook's guidelines. In that case, the best you can do is to appeal to your friend to remove the picture and erase any tags that link it to your profile.