PHP - Blocking of uploaded adult images

Question

We have a setup a product management system where the head of the product development can upload pictures of products and those pictures will instantly show up on our website.

Last week, when one person left the job, he uploaded a bunch of XXX-Rated pictures and things showed up immediately on the website. Luckily, we noticed and removed them in matter of a few minutes. Still, that time was enough to shock some of our customers.

Here is my question: How to effectively analyse and block such images from being uploaded? Can this be done using any library in PHP? Is it possible with PHP in the first place?

Any help would be much appreciated.

Edit 1:

After some digging, I found this:

http://pikture.logikit.net/ (Dead link)

Has anyone used it before, or any opinion about it?

Answer 1

Implement image premoderation. If there's a single person uploading those (like you imply), shouldn't be too hard for someone else to take a brief look and click "Approve" on each.

And it's way cheaper, and more reliable, than using any library. You cannot formalize "adult".

Answer 2

It's a difficult problem in any language, the image processing problem is extremely hard.

There is some research on the subject:

• Appearance-Based Nude Image Detection
• SNIF: a simple nude image finder
• Filtering Objectionable Image Based on Image Content