I would recommend that should a User upload a child porn image, immediately make it inaccessible to the general public. You should then phone your local FBI Field Office and discuss it with them. Ask them what you should do with the image. Provide them with the information they need to go to a DC and serve a search warrant for a copy of the HDD (as that will likely happen if they create a case about it...they will need to receive a direct copy).
DO NOT DELETE THE IMAGE UNTIL CLEARED TO BY LAW ENFORCEMENT. What you have on your server when the image is uploaded is considered evidence of a crime. Deleting the image could constitute destruction of evidence which could in turn land you in hot water.
You also need to ensure you have logs saved for the activity. Additionally, you need to create a log of some sort (excel spreadsheet even) that documents what actions you took and when.
I would honestly recommend retaining a lawyer to go over everything. Technically it's not your legal obligation to report a crime in the US, however, possession and transmission of Child Porn is a federal crime, you want to make sure you're protected.
You will also want to log anyone elses actions on the server regarding the image.
- You receive a report of child pornography. You create a log (like I said, something as simple as an Excel spreadsheet will work)
- You then verify whether it's child porn or not. If it appears like it is, make the image unavailable. Log both of these actions.
- Retain any information about the uploader you have, including IP Address
- Notify the FBI Office in the area of where your server's DC is located. Ask them for guidance on what to do further. Log this information. Continue logging.
- Ensure anyone else with access to the Server logs any actions they take on the server (even if it's not related to the actual image...as minute as an apache process restart) in their own log.
- Sign and notarize them and keep them on file. Turn over originals to FBI if asked.
You will want to include your source location when logging the items.
I say log the items for your personal protection and to document a chain of actions for the evidence should it be used in the prosecution of someone.
Remember, you're not required to do any of this, this is for your protection.
*Source: I was in the US Army Criminal Investigation Command and a Military Police Investigator between 05 and 11.